RikoteMaster/aqua-rat-mcqa huggingface dataset:
Question: How many positive numbers are in a sequence of z numbers, if the sequence alternates between positive and negative numbers and z is an odd number. The sequence starts with a negative number.
A.(z-1)/2
B.z/2
C.z/(2-1)
D.(z+1)/2
Answer: D.(z+1)/2
Explanation: Lets put values for z, say z=7 since it's odd
and first number is neg so sequence will be {neg,pos,neg,pos,neg,pos,neg} we can see that it has 3 negative terms
so putting z=7 in the options,
option D = (z-1)/2 => 7-1/2 = 4 , the number of positive integers
So, D is the answer
Question: 2 hours after train A leaves Lucknow a train B leaves the same stationtraveling in the same direction at an average speed of 28 km/hr. After traveling 6 hrsthe train B overtakes the train A. What is the average speed of the train A?
A.15 km/hr
B.16 km/hr
C.17 km/hr
D.21 km/hr
Answer: D.21 km/hr
Explanation: Explanation :
Total distance covered by B=28*6=168kmTotal time taken by A to cover same distance=2+6=8 hrsaverage speed of A=168/8=21 km/hr
Answer : D
Question: A train moves with a speed of 189 kmph. Its speed in metres per second is
A.60.8
B.18
C.30
D.52.5
Answer: D.52.5
Explanation: Solution
Speed	= 189 Kmph
= (189 x 5/18)m/sec
= 52.5 m/sec.
Answer D
Question: Rajesh can finish 1/3 of his home work in one hour. Seema can finish 3/7 of
her homework in 65 minutes and Ramya can finish 3/4 of her homework in
three and a half hours. If all of them start their home work at 12.00 PM and can
go to play as soon as they all finish their homework. When can they start to
play, if they take a break at 3.00 PM for 35 minutes?
A.4:30pm
B.5:15pm
C.6:30pm
D.5:10pm
Answer: B.5:15pm
Explanation: ajesh can finish his work in 3 hr,
ramya can finish her work in 2.5 hr
seema can finish in 4.6 hr
so 5:15pm they can go to play
ANSWER:B
Question: In the xy-coordinate system, if (m, n) and (m + 3, n + k) are two points on the line with the equation x = 2y + 5, then k =
A.1/2
B.1
C.2
D.3/2
Answer: D.3/2
Explanation: Since (m, n) and (m + 2, n + k) are two points on the line with the equation x = 2y + 5 they should satisfy m=2n +5 and m+3 =2 *(n+k)+5.
By 1st equation we have m-2n=5 and by 2nd equation m-2n = 2k+2 ---> 5=2k+2 --->k=3/2.
The answer is, therefore, (D).
Question: A person purchased a TV set for Rs. 16000 and a DVD player for Rs. 6250. He sold both the items together for Rs. 31150. What percentage of profit did he make?
A.20%
B.96%
C.40%
D.75%
Answer: C.40%
Explanation: The total CP = Rs. 16000 + Rs. 6250
= Rs. 22250 and SP = Rs. 31150
Profit(%)
= (31150 - 22250)/22250 * 100
= 40%
Answer: C
Question: A letter lock consists of four rings each marked with six different letters. The number of distinct unsuccessful attempts to open the lock is at the most ?
A.1340
B.1290
C.1295
D.1288
Answer: C.1295
Explanation: Since each ring consists of six different letters, the total number of attempts possible with the four rings is
= 6 * 6 * 6 * 6= 1296. Of these attempts, one of them is a successful attempt.
Maximum number of unsuccessful attempts
= 1296 - 1
= 1295.
Answer: C
Question: (32323 + 7344 + 41330) - (317 x 91) = ?
A.54210
B.54250
C.52150
D.None of these
Answer: C.52150
Explanation: Its speed and accuracy which decides the winner. You can use various methods including
Vedic mathematics to do complex calculations quickly.
(32323 + 7344 + 41330) - (317 x 91) = 80997 - 28847 = 52150
Answer is C
Question: X divided by Y equals 54.36 what is a possible remainder?
A.5
B.26
C.27
D.34
Answer: C.27
Explanation: With the decimal being 36/100, the simplest form is 9/25. If the divisor is a multiple of 25, the remainder must be a multiple of 9. The only number that is so is 27. Answer C.
Question: Two trains 140 metre and 160 metre long run at the speed of 60 km/hr and 40 km/hr respectively in opposite direction on parallel tracks. What time these will take to cross each other ?
A.10.7 Seconds
B.10.8 Seconds
C.10.9 Seconds
D.11.8 Seconds
Answer: B.10.8 Seconds
Explanation: Explanation:
Relative Speed = 60+40 = 100 Kmph
= 100*(5/18) = 250/9 m/sec
Distance to be covered = 140 + 160 = 300 metres
Time = Distance/Speed
Time=300∗9/250=54/5=10.8 seconds
Option B
Question: How many positive integers less than 100 have a remainder of 5 when divided by 13?
A.5
B.7
C.8
D.9
Answer: A.5
Explanation: We have to include 5 also.As 13*0 + 5 =5
If somebody says to divide 5 by 13 ,we will be telling we have 0 quotient and remainder as 5.
Answer is A
Question: Anand and Deepak started a business investing Rs. 800 and Rs. 1200 respectively. Out of a total profit of Rs. 2000, Deepak's share is:
A.3776
B.2687
C.1200
D.2688
Answer: C.1200
Explanation: Ratio of their shares = 800 : 1200 = 2:3
Deepak's share = 2000 * 3/5 = Rs. 1200.
Answer: C
Question: The product of all the prime numbers less than 27 is closest to which of the following powers of 10?
A.10^9
B.10^8
C.10^7
D.10^6
Answer: B.10^8
Explanation: OA: B
Question: A works thrice as much as B. If A takes 60 days less than B to do a work then find the number of days it would take to complete the work if both work together?
A.22.5 days
B.21.5 days
C.23.5 days
D.24.5 days
Answer: A.22.5 days
Explanation: if A finishes the job in x days
B finishes it in 3x days
3x = x + 60
thus
x = 30
in one hour
1/t = 1/30 + 1/90 = 4/90
where t is the number of days they finish the job together.
t = 90/4 = 22.5 days
ANSWER:A
Question: 1⁄5 of a number is equal to 5⁄8 of the second number. If 35 is added to the first number then it becomes 4 times of second number. What is the value of the second number?
A.125
B.70
C.40
D.25
Answer: C.40
Explanation: Let x be the first number and y be the second number.
1⁄5x = 5⁄8y
\ x⁄y = 25⁄8......(i)
x + 35 = 4y
or, 25⁄8y + 35 = 4y
\ y = 40
Answee C
Question: Calculate the L.C.M of 7/10, 8/ 9, 3/8, 5/12 is :
A.840
B.70
C.740
D.140
Answer: A.840
Explanation: Required L.C.M =L.C.M. of 7, 8, 3, 5/H.C.F. of 10, 9, 8, 12 =840/1=840
Answer is A
Question: A man can row a boat at 13 kmph in still water. If the speed of the stream is 5 kmph, what is the time taken to row a distance of 33 km downstream?
A.11/3
B.11/4
C.11/5
D.11/6
Answer: D.11/6
Explanation: Speed downstream = 13+5=18 kmph.
Time required to cover 60 km downstream = d/s = 33/18=11/6 hours. Answer:D
Question: Find the compound interest and the amount on Rs.8000 at 5% per annum for 3 years when C.I is reckoned yearly?
A.1261
B.1632
C.9177
D.1682
Answer: A.1261
Explanation: A = 8000(21/20)3
= 9261
= 8000
---------
1261
Answer:A
Question: A circular rim 28 inches in a diameter rotates the same number of inches per second as a circular rim 35 inches in diameter. If the smaller rim makes A revolutions per second, how many revilutions per minute does the larger rim makes in terms of A?
A.a) 48pi/A
B.b) 75m
C.c) 48A
D.d) 24A
Answer: C.c) 48A
Explanation: distance covered by a circular wheel per sec* = 2*pi* r * n
where n is number of revolution
So we know the smaller rim makes A rev per sec so the inches coverd SR per sec = 28 * pi* A
the problem the say SR rotates the same number of inches as the LR.
The inches covered by the LR per sec = 35 * pi*Y
So equate both u will get Y = 4/5 X
Theis is in sec we need the answer in min so 48A
answer is C
Question: The population of a town increased from 75,000 to 82,500 in a decade. The average percent increase of population per year is :
A.4.37%
B.5%
C.6%
D.1%
Answer: D.1%
Explanation: Solution
Increase in 10 year= (82500 - 75000) = 7500.
Increase% =( 7500/75000x 100 )% = 10%
âˆ´ Required average = ( 10/10 )% = 1%
Answer D
Question: P beats Q by 5 seconds in a race of 1000 m and Q beats R by 5 metres in a race of 100 m. By how many seconds does P beats R in a race of 1000 m?
A.5 sec
B.7 sec
C.10 sec
D.Can't be determined
Answer: D.Can't be determined
Explanation: Explanation :
If P takes t seconds to run 1000 m, then Q takes (t+5) sec.
In (t+5) sec Q runs 100 m whereas R runs only 950 m.
R runs 1000 m in (1000/950)x(t+5)sec.
P takes t seconds to cover 1000m , while R takes (20t/19+100/95)sec.
From the data given, we cannot determine t .
Answer : D
Question: An artist wishes to paint a circular region on a square poster that is 4 feet on a side. If the area of the circular region is to be 1/2 the area of the poster, what must be the radius of the circular region in feet?
A.1/pi
B.sqrt(8/pi)
C.1
D.2/sqrt(pi)
Answer: C.1
Explanation: Area of the poster is 4x4 = 16
1/2 the area = 8
pi*r^2 = 8
r^2 = 8/pi
r = sqrt(8/pi) answer : C
Question: A certain machine produces 850 units of product P per hour. Working continuously at this constant rate, this machine will produce how many units of product P in 7 days?
A.7,000
B.24,000
C.40,000
D.142,800
Answer: D.142,800
Explanation: Since 7 days consist of 24*7 hours the total hours of a week is 168 hours.
Since every hour the machine produces 850 units of product P the total product during 168 hours is 850*168=142,800.
Correct Option : D
Question: A and B began business with Rs.6000 and Rs.4000 after 8 months, A withdraws Rs.1000 and B advances Rs.1000 more. At the end of the year, their profits amounted to Rs.630 find the share of B.
A.240
B.288
C.273
D.877
Answer: C.273
Explanation: (6*8 + 5*4):(4*8 + 5*4)
17:13
13/30 * 630 = 273
Answer: C
Question: Sum of two numbers is 20. Two times of the first exceeds by 5 from the three times of the other. Then the numbers will be?
A.A)5
B.B)9
C.C)11
D.D)13
Answer: D.D)13
Explanation: Explanation:
x + y = 20
2x – 3y = 5
x = 13 y = 7
D)
Question: Jerry wrote down all the positive integers that have at most 7 digits and
contain only the digits 0 and 1. How many times did he write down the
digit 1 ?
A.128
B.224
C.288
D.448
Answer: D.448
Explanation: Jerry wrote down a total of 27 − 1 = 127 numbers (0 is missing). Add 0 to the
numbers Jerry wrote. We divide the resulting 128 numbers in pairs. If x is one of the
numbers Jerry wrote then we put it in pair with 1111111 − x (whose digits are also 0s
and 1s). For example 1100101 is paired with 11010. In this way, we divide the numbers
into 64 distinct pairs so that each number appears exactly once. Note that there are
exactly 7 digits 1 in each pair. So, Jerry wrote the digit 1 exactly 64 × 7 = 448 times.
correct answer D
Question: The H.C.F. of two numbers is 30 and the other two factors of their L.C.M. are 25 and 24. The larger of the two numbers is
A.276
B.799
C.712
D.750
Answer: D.750
Explanation: Solution
Clearly, the numbers are (30 x 25) and (30 x 24).
Larger number = (30 x 25)	= 750.
Answer D
Question: The least number of complete years in which a sum of money put out at 20% compound interest will be more than doubled is
A.4 years
B.5 years
C.6 years
D.7 years
Answer: A.4 years
Explanation: Explanation:
As per question we need something like following
P(1+R/100)n>2P
(1+20/100)n>2
(6/5)n>2
6/5×6/5×6/5×6/5>2
So answer is 4 years
Option A
Question: A train 125 m long passes a man, running at 5 kmph in the same direction in which the train is going, in 10 seconds. The speed of the train is:
A.38 km/hr
B.40 km/hr
C.44 km/hr
D.50 km/hr
Answer: D.50 km/hr
Explanation: Sol.
Speed of the train relative to man = [125/10] m/sec = [25/2] m/sec.
= [25/2 * 18/5] km/hr = 45 km/hr.
Let the speed of the train be x kmph. Then, relative speed = (x - 5) kmph.
∴ x - 5 = 45 or x = 50 kmph.
Answer D
Question: In a meeting of 3 representatives from each of 6 different companies, each person shook hands with every person not from his or her own company. If the representatives did not shake hands with people from their own company, how many handshakes took place?
A.45
B.135
C.144
D.270
Answer: B.135
Explanation: There are total 18 people from 6 companies,3 from each.Now each of them starts shaking hands one by one with other companies representative. If the companies are A,B,C,D,E,F.
Each member from company A gets to shake hands with 15 people(Total 18 minus member from his company and himself).
Then each member from company B shakes hands with 12 people because they already shook hands with company A members. Similarly company C member shakes hand with 9 members and so on.
so we have (15*3)+(12*3)+(9*3)+(6*3)+(3*3) = 135
ANS:B
Question: If X and Y are digits and 3XY is a 3-digit number that is divisible by 20, which of the following is a possible product of X and Y?
A.45
B.40
C.35
D.23
Answer: B.40
Explanation: Key to this question is to remember the fact that a number divisible by 20 must X is a even, Y is a zero.
Only one answer choice meets the requirement.
Ans B.
Question: Tough and Tricky questions: Word Problems.
If Bill's salary increased by 16 percent, he would earn $812 per month. If instead, his salary were to increase by only 10 percent, how much money Y would he earn per month?
A.$700
B.$754
C.$770
D.$782
Answer: C.$770
Explanation: OFFICIAL SOLUTION:
(C) If Bill’s salary increased by 16% he would earn $812. Algebraically, this can be written as:
$812 = 1.16S, where S is his current salary.
Then S = $812/1.16 = $700.
Now that we know his current salary is $700, we can calculate what his salary would be if it were increased by 10%. We know that 10% of $700 is $70, so his salary would be:
Y=$700 + $70 = $770.
The correct answer is choice (C).
Question: A committee of 6 is chosen from 8 men and 4 women so as to contain at least 2 men and 3 women. How many different committees could be formed?
A.252
B.700
C.1404
D.2620
Answer: A.252
Explanation: The only cases possible are :
1. 2 men and 4 women : 8C2 * 4C4 = 28
2. 3 men and 3 women: 8C3*4C3 = 224
Rest of the cases will either have 1 or 0 men (not allowed) or will have 1 or 2 or 0 women (not allowed)
Total possible combinations = 28+224 = 252. Thus A is the correct answer.
Question: In the faculty of Reverse-Engineering, 226 second year students study numeric methods, 423 second year students study automatic control of airborne vehicles and 134 second year students study them both. How many students are there in the faculty if the second year students are approximately 75% of the total?
A.515.
B.545.
C.618.
D.687.
Answer: D.687.
Explanation: Answer is D :687
Solution : Total number of students studying both are 423 + 226 - 134 = 515 (Subtracting the 134 since they were included in the both the other numbers already).
So 75% of total is 515, so 100% is approx. 687.
Question: A reservoir is provided by two pipes A and B. A can fill the reservoir 5 hours faster than B. If both together fill the reservoir in 6 hours, the reservoir will be filled by A alone in
A.12 hours
B.8 hours
C.10 hours
D.11 hours
Answer: C.10 hours
Explanation: If x is the speed then speed of A= x + 5 and B = x
Time taken by A and B will be x and x + 5 resp.
1/x + 1/x + 5 = 1/6 ; x2 – 7x - 30 = 0 x = -3 or x = 10.
Since time can’t be negative, x =10.
Answer: C
Question: If x = y+3+4.5x and y = x+18, what is the value of x/y ?
A.-6/5
B.-7/20.
C.1/4.
D.5/6.
Answer: C.1/4.
Explanation: Given x = y+3+4.5x --> Eq 1
and y = x+18 --> Eq 2
Here we are asked to find the value of X/Y ?
If you observe eq 1 , then we can understand that if we take Y as X then we get X value very quickly
Let's take X/Y = 1/4 => 4X = Y - eq 3.
Sub this value in eq 1 => we get X = 4X + 3 + 4.5 X
=> - 7.5X = 3
=> X = -2/5 --> Sub X in eq 3 to get Y, we get Y as -8/5.
X/Y = -2/5 / -8/5 => 1/4. we get the same value again.
Answer:option C is correct answer
Question: Jamshid and Irwin decided to make up their own version of basketball. In addition to being able to score 2-point baskets, they created ways to score 5-, 11-, and 13-point baskets. If at halftime the product of the point values of Irwin’s baskets was 2,420, how many 11-point baskets R did Irwin score?
A.0
B.1
C.2
D.3
Answer: C.2
Explanation: First thing I noticed was that all these numbers are prime...
Prime factorization gives the following
Step 1:2*1210
Step 2:2*11*110
Step 4:2*11*11*10
Step 5:2*11*11*2*5
So he scored R=2 11-point baskets in my opinion.
Answer C
Question: The least number of complete years in which a sum of money put out at 20% C.I. will be more than doubled is?
A.5
B.4
C.7
D.9
Answer: B.4
Explanation: P(1 + 20/100)n > 2P or (6/5)n > 2
Now, (6/5 * 6/5 * 6/5 * 6/5) > 2. So,
n = 4 years.
Answer: B
Question: A die is thrown. If G is the event 'the number appearing is a multiple of 3' and H be the event
'the number appearing is even' then find whether G and H are independent ?
A.G and H are not independent events.
B.G and H are independent events.
C.Only G independent event
D.Only H independent event
Answer: B.G and H are independent events.
Explanation: We know that the sample space is S = {1, 2, 3, 4, 5, 6}
Now G = { 3, 6}, F = { 2, 4, 6} and E n F = {6}
Then P(G) = 2/6 = 1/3
P(H) = 3/6 = 1/2 and P(G ∩ H) = 1/6
P(G n H) = P(G). P (H)
G and H are independent events.
B
Question: A runner runs the 40 miles from Marathon to Athens at a constant speed. Halfway through the run she injures her foot, and continues to run at half her previous speed. If the second half takes her 4 hours longer than the first half, how many hours did it take the runner to run the second half?
A.6
B.7
C.8
D.9
Answer: C.8
Explanation: The runner runs the first 20 miles at speed v and the second 20 miles at speed v/2.
The time T2 to run the second half must be twice the time T1 to run the first half.
T2 = 2*T1 = T1+4
T1 = 4 and so T2 = 8.
The answer is C.
Question: Divide Rs. 2379 into 3 parts so that their amounts after 2, 3 and 4 years respectively may be equal, the rate of interest being 5% per annum at simple interest. The first part is?
A.227
B.299
C.266
D.828
Answer: D.828
Explanation: Let the parts be x, y and [2379 - (x + y)]
x + (x * 2 * 5/100) = y + (y * 3 * 5/100) = z + (z * 4 * 5/100)
11x/10 = 23y/20 = 6z/5 = k
x = 10k/11, y = 20k/23, z = 5k/6
But x + y + z = 2379
10k/11 + 20k/23 + 5k/6 = 2379
k = (2379 * 11 * 23 * 6)/3965 = (3 * 11 * 23 * 6)/5
x = [10/11 * (3 * 11 * 23 * 6)/5] = 828
Hence, the first part is Rs. 828.
Answer: D
Question: A person covered one-fourth of the total distance at 18 kmph and remaining distance at 24 kmph. What is the average speed for the total distance?
A.21 (1/18)
B.21 (1/13)
C.21 (8/13)
D.22 (2/13)
Answer: D.22 (2/13)
Explanation: Let the total distance be x km
total time taken = (x/4)/18 + (3x/4)/24 = 13x/288
Average speed = x/(13x/288) = 22 (2/13)kmph.
Answer: D
Question: The average of 10 consecutive odd numbers is 22. What is the sum of the first 3 numbers?
A.13
B.45
C.17
D.220
Answer: B.45
Explanation: 22 = (n + n+2 + n + 4 + ... + (n + 18))/10
22 = (10n + (2 + 4 + ... + 18))/10
220 = 10n + 2(1 + 2 + ... + 9)
220 = 10n + 2(9)(10)/2
220 = 10n + 90
220 - 90 = 10n
130 = 10n
n = 13
So the first three numbers are 13, 15, 17
13 + 15 + 17 = 45
Option B
Question: How many three digit numbers Q are divisible by 78 or 91?
A.17
B.19
C.20
D.21
Answer: B.19
Explanation: The answer will be 19.
Explanation:
78= 2*3*13 now multiples of 78, 156 ....780, now 1000-780 = 220 only two more muktiples of 78 can exists. So total number of 3 digit Multiples of 78 are 9+2=11
91= 13*7--Total number of three digit multiples --9
No remember we have a common multiples as well-- 13*7*6=91*6=546
So total number of multiples Q --11+9 -1 =19.
Hence Answer is 19.B
Question: How many positive integers less than 5,000 are evenly divisible by neither 17 nor 21?
A.4,514
B.4,480
C.4,521
D.4,428
Answer: B.4,480
Explanation: integers less than 5000 divisible by 17 5000/17 =333.something , so 333
integers less than 5000 divisible by 21 5000/21 = 238.## , so 238
we have double counted some, so take LCM of 17 and 21 =105 and divide by 5000, we get 47. so all numbers divisible by 17 and 21 = 333 +238 -47 =524
now subtract that from 4999. 4999- 524 = 4480 answer B.
Question: A trade analyst announced 8% reduction in the unit price of bike. As a result, the sales volume went up by 20%. What was the net effect on the sales revenue?
A.no change
B.decreases by 10.4%
C.increases by 10.4%
D.increases by 10%
Answer: C.increases by 10.4%
Explanation: Explanation :
Reduction of price = (100 -8)% = 92% = 0.92
Increase of sale = (100+20)% = 120% = 1.20
Total effect = 0.92 X 1.20 = 110.4%, Increases by 10.4%
Answer : C
Question: What least number should be added to 1057, so that the sum is completely divisible by 23
A.A)4
B.B)1
C.C)2
D.D)3
Answer: B.B)1
Explanation: Explanation:
(1057 / 23) gives remainder 22
22 + 1 = 23, So we need to add 1
Answer: Option B
Question: If 3 taps are opened together a tank is filled in 3 hrs. One of the taps alone can fill it in 10 hrs. and another in 15 hrs. In how many hours will the third tap fill it ?
A.7 hrs.
B.4 hrs.
C.5 hrs.
D.6 hrs.
Answer: D.6 hrs.
Explanation: Part filled by three taps together in 1 hr =1/3 Part filled by one of the tap in 1 hr =1/10 Part filled by another tap in 1 hr =1/15 Part filled by third tap in 1 hr =1/3-(1/0+1/15) =5/30 Therefore the third tap can fill the whole tank in : 30/5 hrs. =6 hrs. Answer : D
Question: In the middle of a round pool lies a beautiful water lily. The water lily doubles in size every day. After exactly 20 days, the lily will cover the complete pool. After how many days will the water lily cover half of the pool?
A.16
B.18
C.19
D.10
Answer: C.19
Explanation: C
Because the water lily doubles its size every day and the complete pool is covered after 20 days, half of the pool will be covered one day before that, after 19 days.
Conclusion: after 19 days, the water lily will cover half of the pool.
Question: There are two sections A and B of a class, consisting of 36 and 44 students respectively. If the average weight of sections A is 40 kg and that of section b is 35 kg. Find the average weight of the whole class?
A.36.25
B.37.25
C.38.25
D.17.25
Answer: B.37.25
Explanation: 36*40=1440
44*35=1540
1440+1540=2980
2980/(36+44)=37.25
ANSWER:B
Question: A train running at the speed of 60 km/hr crosses a pole in 12 seconds. Find the length of the train?
A.150 meter
B.876 meter
C.200 meter
D.719 meter
Answer: C.200 meter
Explanation: Speed = 60*(5/18) m/sec = 50/3 m/sec
Length of Train (Distance) = Speed * Time
(50/3) * 12
= 200 meter
Answer: C
Question: If both m and n are negative integers, which of the following must be positive?
A.m/n-1
B.m(n+1)
C.mn-5
D.m^2+n^2-1
Answer: D.m^2+n^2-1
Explanation: Given m and n are negative integers.
Now take m = -1 and n = -1. sub these values in options..
A) m/n-1 = -1/-1 - 1 = 0.
B. m(n+1) = 0
C. mn-5 = -4
D. m^2+n^2-1 = 1
E. mn+3n = -4
If we take any negative value , say m = -1 or n = -2 etc..only D satisfies...
ANSWER:D
Question: Which fraction should be added to:
1/(2 Ã— 3) + 1/(3 Ã— 4) + 1/(4 Ã— 5) + ....... + 1/(27 Ã— 28)
so that the result is equal to 1?
A.11/28
B.13/28
C.15/28
D.17/28
Answer: C.15/28
Explanation: The given expression
= 1/(2 Ã— 3) + 1/(3 Ã— 4) + 1/(4 Ã— 5) + ...... + 1/(27 Ã— 28)
= (1/2 - 1/3) + (1/3 - 1/4) + (1/4 - 1/5) + .......... + (1/27 - 1/28)
= 1/2 - 1/28 = 13/28
Thus, the fraction we should add = 1 - 13/28 = 15/28
The answer is C.
Question: A and B complete a work in 6 days. A alone can do it in 10 days. If both together can do the work in how many days?
A.3.75 days
B.3.99 days
C.2.99 days
D.2.98 days
Answer: A.3.75 days
Explanation: 1/6 + 1/10 = 8/30 = 4/15
15/4 = 3.75 days
Answer: A
Question: A college has classes from 10:00 AM until 1:50 PM. In this duration, there are five periods. If 5 minutes are provided between each period to leave one class and enter the next class, how many minutes long is each period?
A.38 min
B.41 min
C.40 min
D.42 min
Answer: D.42 min
Explanation: The total time is 230 minutes.
There are four breaks of five minutes between the classes for a total of 20 minutes.
The total class time is 210 minutes.
210 / 5 classes = 42 minutes per class
The answer is D.
Question: The current birth rate per thousand is 42, whereas corresponding death rate is 15 per thousand. The net growth rate in terms of population increase in percent is given by
A..027%
B.27%
C.2.7%
D..0027%
Answer: C.2.7%
Explanation: Sol.
Net growth on 1000 = (42 - 15) = 27.
Net growth on 100 = (27/1000 Ã— 100)% = 2.7%.
Answer C
Question: The sum of two numbers is 77. Five times one number is equal to 6 times the other. The bigger of the two numbers is
A.10
B.42
C.14
D.15
Answer: B.42
Explanation: a:b 5:6
a+b=77
5x+6x=77
x=7
then two numbers are 35,42. The bigger number is 42
ANSWER:B
Question: In a ratio, which is equal to 3 : 4, if the antecedent is 12, then the consequent is
A.6
B.9
C.16
D.10
Answer: C.16
Explanation: Sol.
We have 3/4 = 12/x ⇔ 3x = 48 ⇔ x = 16.
∴ Consequent = 16.
Answer C