RikoteMaster/aqua-rat-mcqa huggingface dataset:
Question: Each writer for the local newspaper is paid as follows: a dollars for each of the first n stories each month, and a + b dollars for each story thereafter, where a > b. How many more dollars will a writer who submits n + a stories in a month earn than a writer who submits n + b stories?
A.(a – b)( a + b + n)
B.a – b
C.a^2 – b^2
D.n( a – b)
Answer: C.a^2 – b^2
Explanation: total earned for n+a stories =a + a(a+b)
total earned for n+b stories =a+ b(a+b)
difference = a+a(a+b) -a -b(a+b)
=(a+b)(a-b) =a^2-b^2
ANSWER:C
Question: A number is doubled and 6 is added. If resultant is trebled, it becomes 72. What is that number
A.8
B.10
C.9
D.14
Answer: C.9
Explanation: Explanation:
=> 3(2x+6) = 72
=> 2x+6 = 24
=> x = 9
Option C
Question: A train after traveling for 50km meets with an accident and then proceeds at 3/4 of its former speed and arrives at its destination 35 minutes late . Had the accident occurred 24 km farther, it would have reached the destination only 25 minutes late. What is the speed Y of the train.
A.a) 45
B.b) 33
C.c) 48
D.d) 55
Answer: C.c) 48
Explanation: Let y be the balance distance to be covered and x be the former speed.
A train after traveling for 50km meets with an accident and then proceeds at 3/4 of its former speed and arrives at its destination 35 minutes late
so, y/(3x/4) - y/x = 35/60
4y/3x - y/x = 7/12
y/x(4/3-1)=7/12
y/x*1/3=7/12
y/x=7/4
4y-7x=0 ........ 1
Had the accident occurred 24 km farther, it would have reached the destination only 25 minutes late
so, (y-24)/(3x/4) - (y-24)/x = 25/60
4(y-24)/3x - (y-24)/x = 5/12
(y-24)/x (4/3-1) = 5/12
(y-24)/x *1/3 = 5/12
(y-24)*12 = 3x*5
(y-24)*4 = 5x
4y-5x = 96 ....... 2
eq2 - eq1
2x=96
x=48=Y
Ans = C
Question: Sushi invested an amount of Rs. 10,000 at the rate of 15% p.a simple interest and another amount at the rate of 16% p.a. simple interest. The total interest earned at the end of one year on the total amount invested became 14% p.a. Find the total amount invested?
A.10900
B.10800
C.10500
D.10600
Answer: A.10900
Explanation: Let the second amount be Rs. x. Then,
(10000 * 15 * 1)/100 + (x * 16 * 1)/100 = [(12000 + x) * 14 * 1] / 100
15000+ 16x= 16800 + 14x
x = 900
Total investment = 10000 + 900 = Rs. 10,900.Answer: A
Question: Insert the missing number
165, 195, 255, 285, 345, ...
A.375
B.420
C.435
D.390
Answer: A.375
Explanation: 165, 195, 255, 285, 345, ...has two different seriers with 90 difference between two numbers
165, 255, 345...
195, 285, ..... 375 is the next number
ANSWER:A
Question: In an office, totally there are 6400 employees and 65% of the total employees are males. 25% of the males in the office are at-least 50 years old. Find the number of males aged below 50 years?
A.2882
B.8277
C.3120
D.2777
Answer: C.3120
Explanation: Number of male employees = 6400 * 65/100 = 4160
Required number of male employees who are less than 50 years old = 4160 * (100 - 25)%
= 4160 * 75/100 = 3120.
Answer: C
Question: The length of a rectangle is reduced by 30%. By what % would the width have to be increased to maintain the original area?
A.42.8%
B.20%
C.25%
D.30%
Answer: A.42.8%
Explanation: Sol. Required change = (30*100)/(100-30)=42.8%
A
Question: The length of rectangle is thrice its breadth and its perimeter is 96 m, find the area of the rectangle?
A.432
B.376
C.299
D.276
Answer: A.432
Explanation: 2(3x + x) = 96
l = 36 b = 12
lb = 36 * 12
= 432
A
Question: Pipe A can fill a tank in 12 hours. Due to a leak at the bottom it takes 20 hours to fill the tank. In what time the leak alone can empty the full tank?
A.18 hours
B.23 hours
C.28 hours
D.30 hours
Answer: D.30 hours
Explanation: Let leak can empty the full tank in x hours.
1/12- 1/X = 1/20
=> 1/12 – 1/20 = 1/X
1/X =5-3 /60= 1/30
x= 30 hours
ANSWER:D
Question: From a pack of 52 cards, one card is drawn. What is the probability that the card is a color of red?
A.1/6
B.2/2
C.1/2
D.8/2
Answer: C.1/2
Explanation: Let S be the sample space. Then,
n(S) = 52C1	= 52.
Let E = event of getting 1 face card.
n(E) = number of ways of choosing 1 face card out of 26
=26C1 = 26
P(E) = n(E) / n(S)	= 26 / 52
= 1/2.
Answer C
Question: A father said to his son, "I was as old as you are at the present at the time of your birth". If the father's age is 38 years now, the son's age five years back was:
A.14 years
B.19 years
C.33 years
D.38 years
Answer: A.14 years
Explanation: Explanation:
Let the son's present age be x years. Then, (38 - x) = x
2x = 38.
x = 19.
Son's age 5 years back (19 - 5) = 14 years.
Answer: A
Question: Which of the following is a prime number ?
A.33
B.81
C.93
D.97
Answer: D.97
Explanation: Explanation:
Clearly, 97 is a prime number. Because it is not divisible by other numbers.
ANSWER IS D
Question: John found that the average of 15 numbers is 40. If 10 is added to each number then the mean of number is?
A.50
B.65
C.70
D.75
Answer: A.50
Explanation: (x+x1+...x14)/15 = 40
50
Option A
Question: A train is 300 meter long is running at a speed of 54 km/hour. In what time will it pass a tunnel of 1200 meter length?
A.90 seconds
B.85seconds
C.40 seconds
D.100 seconds
Answer: D.100 seconds
Explanation: Speed = 54 Km/hr = 54*(5/18) m/sec = 15 m/sec
Total distance = 300+1200 = 1500 meter
Time = Distance/speed
= 1500 * (15) = 100 seconds
Answer: D
Question: A train has a length of 150 meters . it is passing a man who is moving at 2 km/hr in the same direction of the train, in 3 seconds. Find out the speed of the train.
A.182 km/hr
B.180 km/hr
C.152 km/hr
D.169 km/hr
Answer: A.182 km/hr
Explanation: Explanation:
Length of the train, l = 150m
Speed of the man , Vm= 2 km/hr
Relative speed, Vr = total distance/time = (150/3) m/s = (150/3) × (18/5) = 180 km/hr
Relative Speed = Speed of train, Vt - Speed of man (As both are moving in the same direction)
=> 180 = Vt - 2
=> Vt = 180 + 2 = 182 km/hr
Answer: Option A
Question: Four barrels of water have an average capacity of 8 gallons. What is the maximum possible capacity of the smallest barrel E if the median is 10 gallons?
A.1
B.2
C.3
D.4
Answer: B.2
Explanation: Suppose 4 barrels are B1, B2, B3, B4 in ascending capacity.
(B1+B2+B3+B4)/4 = 8
B1+B2+B3+B4=32
median is 10 ....... as the no. of terms are even i.e 4, median = (B2+B3)/2
==> B2+B3 = 20
now we have B1+B4 = 32-20 =12
Only the following possible cases can be there :
1,9,11,11
1,10,10,11
2,10,10,10
Max value of smallest barrel E= 2=B
Question: A train running at the speed of 60 km/hr crosses a pole in 9 seconds. Find the length of the train.
A.150
B.88
C.2767
D.288
Answer: A.150
Explanation: Speed = 60*(5/18) m/sec = 50/3 m/sec
Length of Train (Distance) = Speed * Time
(50/3) * 9 = 150 meter
Answer: A
Question: How many 3x3x3 cubes could fit in a 10x24x16 box?
A.150
B.145
C.138
D.142
Answer: D.142
Explanation: The answer is D) 142. The 10x24x16 box has an area of 3840. If you divide it by 27 (the total of the 3x3x3 smaller cube) you get 142.2. This means you could fit 142 whole cubes in the larger box.
Question: An bus covers a certain distance at a speed of 240 kmph in 5 hours. To cover the samedistance in 1hr, it must travel at a speed of?
A.677 km/hr
B.720 km/hr
C.790 km/hr
D.800 km/hr
Answer: B.720 km/hr
Explanation: Distance = (240 x 5) = 1200 km.
Speed = Distance/Time
Speed = 1200/(5/3) km/hr. [We can write 1 hours as 5/3 hours]
Required speed = 1200 x 3 km/hr = 720 km/hr.
B
Question: A soccer team played 280 games and won 65 percent of them. How many games did it win?
A.182
B.100
C.104
D.150
Answer: A.182
Explanation: 65% of 280 =x
0.65*280 = x
182=x
answer :A
Question: In a lottery, there are 9 prizes and 18 blanks. A lottery is drawn at random. What is the probability of getting a prize?
A.1/2
B.1/3
C.1/4
D.1/5
Answer: B.1/3
Explanation: P(winning a prize) = 9 / (9+18) = 9/27 = 1/3
The answer is B.
Question: The difference between a positive proper fraction and its reciprocal is 9 / 20. Then the fraction is :
A.4/0
B.4/1
C.4/5
D.4/2
Answer: C.4/5
Explanation: Explanation:
Let the required fraction be x. Then, (1 / x )- x = 9/20
1 - x^(2) / x = 9 / 20 => 20 - 20 * x^(2) = 9 * x.
20 * x^(2) + 9 *x - 20 = 0.
=> (4 * x + 5) (5 * x - 4) = 0.
=> x = 4 / 5.
Answer: C) 4/5
Question: Two pipes P and Q can fill a cistern in 12 and 15 minutes respectively. Both are opened together, but at the end of 3 minutes the first is turned off. How much longer will the cistern take to fill?
A.11 1/8
B.11 1/4
C.11 2/4
D.12 1/4
Answer: B.11 1/4
Explanation: 3/12 + x/15
= 1
x= 11 1/4
Answer: B
Question: A train running at 1/2 of its own speed reached a place in 8 hours. How much time could be saved if the train would have run at its own speed?
A.8hrs
B.10hrs
C.4 hrs
D.15hrs
Answer: C.4 hrs
Explanation: time taken if run its own speed = 1/2*8 =4 hrs
Time saved = 8 - 4 = 4 hrs
Answer : C
Question: A car covers a distance of 813 km in 3 hours. Find its speed?
A.104
B.288
C.271
D.276
Answer: C.271
Explanation: 813/3 = 271 kmph
Answer: C
Question: How many 3 letter (not necessarily distinct) words can be formed using the letters from the word TWIST ?
A.33
B.54
C.45
D.60
Answer: A.33
Explanation: Two T's are used
In this case we have to select just one letter out of the remaining 33 (W, I, S) which can be arranges in 3 places.
So, the total possibilities are 3∗3=9
Total possibilities 24+9=332
So, the answer is A.
Question: In each series, look for the degree and direction of change between the numbers. In other words, do the numbers increase or decrease, and by how much? Look at this series: 120, 30, 240, 25, ___, 20, 480, 15... Which number is missing?
A.120
B.360
C.340
D.960
Answer: B.360
Explanation: B 360This is an alternating addition and subtraction series. In the first pattern, 120 is added to each number to arrive at the next. In the second, 5 is subtracted from each number to arrive at the next.
Question: If x+y=250, x-y=200, for integers of x and y, y=?
A.200
B.225
C.50
D.115
Answer: B.225
Explanation: x+y = 250
x-y = 200
2x = 50
x = 25
y = 225
Answer is B
Question: A tank is 25m long 12m wide and 6m deep. The cost of plastering its walls and bottom at 75 paise per sq m is
A.Rs. 258
B.Rs. 358
C.Rs. 458
D.Rs. 558
Answer: D.Rs. 558
Explanation: Explanation:
Area to be plastered = [2(l + b) × h] + (l × b)
= [2(25 + 12) × 6] + (25 × 12) = 744 sq m
Cost of plastering = 744 × (75/100) = Rs.558 Answer: D
Question: A student scored an average of 80 marks in 3 subjects: Physics, Chemistry and Mathematics. If the average marks in Physics and Mathematics is 90 and that in Physics and Chemistry is 70, what are the marks in Physics?
A.86
B.16
C.76
D.80
Answer: D.80
Explanation: Given M + P + C = 80 * 3 = 240 --- (1)
M + P = 90 * 2 = 180 --- (2)
P + C = 70 * 2 = 140 --- (3)
Where M, P and C are marks obtained by the student in Mathematics, Physics and Chemistry.
P = (2) + (3) - (1) = 180 + 140 - 240
= 80
Answer:D
Question: A man can ride on cycle at 35 kmph upward road and 70 kmph downward road. He takes 6 hours to cycle uphill from lower point A to upper point B and back to A. What is the total distance traveled by him in 6 hours? He must return back to base point A in remaining time
A.120
B.140
C.160
D.280
Answer: D.280
Explanation: Upward distance traveled per hour - 35 km,
distance traveled after 4 hours = 140 km.
He remained with 2 hours travel downward, i.e. distance traveled in remaining 2 hours downward = 140 km
so total distance traveled from A to B and Back to point A = 140 km upward + 140 km downhill = 280 km
(Answer : D)
Question: At a certain bowling alley, it costs $0.50 to rent bowling shoes for the day and $1.25 to bowl 2 games. If a person has $12.80 and must rent shoes, what is the greatest number of complete games that person can bowl in one day?
A. 7
B. 8
C. 9
D. 19
Answer: D. 19
Explanation: After renting bowling shoes the person is left with $12.80-$0.5=$12.30, which is enough for 12.3/1.25=9.84(2)=19.68<21. ~ 19 games
Answer: D.
Question: Ram has $100 in her piggy bank. How much will she have in her bank 25 weeks from now if she puts $1 in the bank next week, $2 two weeks from now, $3 three weeks from now, and continues to increase the amount that she puts in by $1 each week?
A.400
B.415
C.425
D.435
Answer: C.425
Explanation: The dollar deposits are in an A.P.
1,2,3,4...25 with common difference 1
Sum of the terms is n(n+1) / 2
i.e 25* (25+1) /2
= 25* 26/2 = 325
Total deposit therefore with Chiu-Lihas is 100 + 325= 425$
Question: If the price of petrol increases by 20, by how much must a user cut down his consumption so that his expenditure on petrol remains constant?
A.16.7%
B.20%
C.24.67%
D.33.33%
Answer: A.16.7%
Explanation: Explanation :
let us assume before increase the petrol will be Rs. 100.
After increase it will be Rs (100+20) i.e 120.
Now, his consumption should be reduced to :-
=(120−100)/120 ∗ 100.
Hence, the consumption should be reduced to 16.7%.
Answer : A
Question: probability that guy1 will succesfully hit a shot is 2/3. probabilty of guy2 succesfully hitting a shot is 2/3. if they shoot two shots each, what is the probability that they have equal number of hits?
A.9/27
B.10/27
C.11/27
D.12/27
Answer: C.11/27
Explanation: (1/3*1/3)[guy1]*(1/3*1/3)[guy2]
for 1 hit each: (4 ways)
(2/3*1/3)*(2/3*1/3), (2/3*1/3)*(1/3*2/3), (1/3*2/3)*(2/3*1/3), (1/3*2/3)*(1/3*2/3)
for 2 hits each:(1 way)
(2/3*2/3)*(2/3*2/3)
Add all these cases, you will get answer as 11/27.
ANSWER:C
Question: It takes Tammy 15 minutes to do one oil change, and it takes Jill 10 minutes. At 2:30 pm, they both finish an oil change simultaneously. If Tammy and Jill both began doing oil changes at exactly the same time and worked without pausing, when did they both start doing oil changes?
A.2:00 pm
B.2:05 pm
C.2:10 pm
D.2:15 pm
Answer: A.2:00 pm
Explanation: Since Tammy finishes s oil changes after s × 15 minutes and Jill finishes c oil changes after c × 10 minutes, they both finished doing an oil change at the same time when s × 15 = c × 10. Since s and c must be integers (they represent the number of oil changes finished) this question is asking you to find a common multiple of 15 and 10. The question asks for the first time they began a car simultaneously, so you must find the least common multiple and subtract. The least common multiple of 15 and 10 is 30, so in the context of the question, this would be 30 minutes. Therefore, they began changing the oil of a car at the same time at 2:30 - 30 minutes, or 2:00 p.m. The answer is (A).
Question: How many four digit numbers can be formed using the digits {1, 3, 4, 5, 7,9}(repetition of digits is not allowed)?
A.360
B.838
C.372
D.737
Answer: A.360
Explanation: The given digits are six.
The number of four digit numbers that can be formed using six digits is ⁶P₄ = 6 * 5 * 4 * 3
= 360.
Answer:A
Question: If TRAIN is coded as 12 and PANDA is coded as 18, then CURED is coded as
A.5
B.10
C.13
D.20
Answer: A.5
Explanation: TRAIN= 20+18+1+9+14=62 i.e 6*2=12
PANDA= 16+1+14+4+1=36 i.e 3*6=18
CURED= 3+21+18+5+4=51 5*1=5
ANSWER:A
Question: Eight years back, a father was 52 years older than his son. At present the father is 5 times as old as the son. How old will the son be three years from now?
A.10 years
B.12 years
C.14 years
D.16 years
Answer: D.16 years
Explanation: Using linear equations to convert the word problem:
** F = fathers current ageS = sons current age
#1 Eight years back, a father was 52 years older than his son: F-8 = 52 + (S - 8)
#2 At present the father is 5 times as old as the son: F = 5*S
How old will the son be three years from now?: S + 3 = ?
With two variables and two linear equations we are able to solve the problem:
(S*5) - 8 = 52 +S -8
4S=52
S = 13
S + 3 = 13+ 3 = 16
Answer: D
Question: A water tank is two-fifth full. Pipe A can fill a tank in 10 minutes and pipe B can empty it in 6 minutes. If both the pipes are open, how long will it take to empty or fill the tank completely?
A.2 min. to empty
B.3 min. to empty
C.6 min. to empty
D.7 min. to empty
Answer: C.6 min. to empty
Explanation: Clearly, pipe B is faster than pipe A and so, the tank will be emptied.
Part to be emptied = 2/5
Part emptied by (A + B) in 1 minute = (1/6 - 1/10) = 1/15
1/15 : 2/5 :: 1 : x
x = (2/5 * 1 * 15) = 6 min.
So, the tank will be emptied in 6 min.
ANSWER:C
Question: A Shopkeeper earns a profit of 12% on selling a book at 10% discount on the printed. The ratio of the cost price and the printed price of the book is:
A.12:24
B.29:23
C.32:41
D.45:56
Answer: D.45:56
Explanation: Explanation:
Printed price of the book is Rs. 100
After a discount of 10% S.P = Rs. 90
Profit earned = 12%
C.P of the book = Rs. (100/112 × 90) = Rs. 1125/14
(C.P) : (Printed price) = 1125/14 : 100 or 45 : 56
Answer: Option D
Question: A can do a piece of work in 4 days. B can do it in 6 days. With the assistance of C they completed the work in 2 days. Find in how many days can C alone do it?
A.87 days
B.12 days
C.16 days
D.19 days
Answer: B.12 days
Explanation: C = 1/2 - 1/4 - 1/6 = 1/12
=> 12 days
Answer:B
Question: In 10 years, A will be twice as old as B was 10 years ago. If A is now 6 years older than B the present age of B is
A.37
B.36
C.39
D.40
Answer: B.36
Explanation: let present age of A be a and B be b
a+10 = 2*(b-10)
=> 2b-a = 30 ......(i)
a = b+6
=>2b-b-6 = 30
b=36
so the present age of b is 36 years
ANSWER:B
Question: A boat having a length 3 m and breadth 2 m is floating on a lake. The boat sinks by 1 cm when a man gets on it. The mass of the man is:
A.65 kg
B.62 kg
C.120 kg
D.60 kg
Answer: D.60 kg
Explanation: Volume of water displaced	= (3 x 2 x 0.01) m3
= 0.06 m3.
Mass of man	= Volume of water displaced x Density of water
= (0.06 x 1000) kg
= 60 kg.
ANSWER D
Question: The sum of the present ages of two persons A and B is 60. If the age of A is twice that of B, find the sum of their ages 3 years hence?
A.58
B.59
C.62
D.66
Answer: D.66
Explanation: Explanation:
A + B = 60, A = 2B
2B + B = 60 => B = 20 then A = 40.
3 years, their ages will be 43 and 23.
Sum of their ages = 43 + 23 = 66.
D)
Question: A “Sophie Germain” prime is any positive prime number p for which 2p + 1 is also prime. The product of all the possible units digits of Sophie Germain primes greater than 5 is
A.3
B.7
C.21
D.27
Answer: D.27
Explanation: A prime number greater than 5 can have only the following four units digits: 1, 3, 7, or 9.
If the units digit of p is 1 then the units digit of 2p+1 would be 3, which is a possible units digit for a prime. For example consider p=11=prime --> 2p+1=23=prime;
If the units digit of p is 3 then the units digit of 2p+1 would be 7, which is a possible units digit for a prime. For example consider p=23=prime --> 2p+1=47=prime;
If the units digit of p is 7 then the units digit of 2p+1 would be 5, which is NOT a possible units digit for a prime;
If the units digit of p is 9 then the units digit of 2p+1 would be 9, which is a possible units digit for a prime. For example consider p=29=prime --> 2p+1=59=prime.
The product of all the possible units digits of Sophie Germain primes greater than 5 is 1*3*9=27.
Answer: D.
Question: A train covers a distance of 12 km in 10 minutes.If it takes 6 seconds to pass a telegraph post,then the length of the train is
A.90m
B.100m
C.120m
D.140m
Answer: C.120m
Explanation: Speed=(12/10*60)km/hr=(72*5/18)m/sec=20m/sec
Length of the train=(Speed *Distance)
=(20*6)m=120m
Answer:Option C
Question: Sachin is younger than Rahul by 7 years. If the ratio of their ages is 7:9, find the age of Sachin
A.24.5
B.24.8
C.24.21
D.24.88
Answer: A.24.5
Explanation: Explanation:
If Rahul age is x, then Sachin age is x - 7,
so,
9x - 63 = 7x
2x = 63
x = 31.5
So Sachin age is 31.5 - 7 = 24.5
Answer: A) 24.5
Question: Pipe P can fill a tank in 8 hours, pipe Q in 12 hours and pipe R in 20 hours. If all the pipes are open, in how many hours will the tank be filled?
A.2 hours
B.2.4 hours
C.3.8 hours
D.3.5 hours
Answer: C.3.8 hours
Explanation: Explanation:
Part filled by (P + Q + R) in 1 hour = (1/8 + 1/12 + 1/20) = 31/120
All the three pipes together will fill the tank = 120/31 = 3.8 hours
ANSWER C
Question: A car covers a distance of 648 km in 6 ½ hours. Find its speed?
A.104 kmph
B.176 kmph
C.108 kmph
D.186 kmph
Answer: C.108 kmph
Explanation: 648/6
= 108 kmph
Answer:C
Question: What is the sum of all even numbers from 1 to 701?
A.122821
B.281228
C.281199
D.122850
Answer: D.122850
Explanation: Explanation:
700/2 = 350
350 * 351 = 122850
Answer: D
Question: Find the area of the quadrilateral of one of its diagonals is 50 cm and its off sets 10 cm and 8 cm?
A.189 cm2
B.150 cm2
C.127 cm2
D.450 cm2
Answer: D.450 cm2
Explanation: 1/2 * 50(10 + 8)
= 450 cm2
Answer: D
Question: If r and s are positive integers and r-s=6, which of the following has the greatest value E?
A.2r
B.2s
C.r +s
D.2r-s
Answer: A.2r
Explanation: The simplest way to do this is to assume values.
We are told that r and s are positive integers E.
Also, r-s = 6 => r = 6+s
Hence r is 6 more than s.
Let s be 10. Hence r = 16.
Option A: 2r = 2*16 = 32
Option B: 2s = 2 * 10 = 20
Option C: r + s = 16 + 10 = 26
Option D: 2r - s = 2(16) - 10 = 32 - 10 = 22
Option E: 2s - r = 2(10) - 16 = 20 - 16 = 4
Hence option A is the greatest.
Question: In the city of San Durango, 60 people own cats, dogs, or rabbits. If 34 people owned cats, 40 owned dogs, 10 owned rabbits, and 12 owned exactly two of the three types of pet, how many people owned all three?
A.2
B.6
C.8
D.12
Answer: B.6
Explanation: Total = C + D + R - (CD + DR + CR) - 2CDR
60 = 34 + 40 + 10 - (12) - 2x
x = 6
So, answer will be B
Question: Find the odd man out. 187, 264, 306, 473, 682, 781
A.187
B.306
C.781
D.682
Answer: B.306
Explanation: In all numbers except 306, the middle digit is the sum of other two digits.Answer is B
Question: A store reported total sales of $385 million for February of this year. If the total sales for the same month last year was $320 million, approximately what was the percent increase I in sales?
A. 2%
B. 17%
C. 20%
D. 65%
Answer: C. 20%
Explanation: Last year's sales = $320 million;
This year's sales = $385 million;
Increase I = $65 million.
Now, 20% of $320 million is $64 million, which is very close to actual increase of $65 million.
Answer: C.
Question: Out of five consonants and three vowels, how many words can be made so that each word contains two consonants and three vowels?
A.800
B.1000
C.1200
D.1600
Answer: C.1200
Explanation: 5C2 x 3C3 x 5! = 1200
The answer is C.
Question: The ratio of expenditure and savings is 3 : 2 . If the income increases by 15% and the savings increases by 6% , then by how much percent should his expenditure increases?
A.22
B.21
C.88
D.76
Answer: B.21
Explanation: Answer: B) 21
Question: Tough and Tricky questions: Exponents.
If a and b are positive integers and x = 6^a and y = 9^b, which of the following is a possible units digit of xy?
A.1
B.6
C.5
D.7
Answer: B.6
Explanation: Only Units digit of X and Y contribute to the Units digit of XY.
Finding all values of X for positive values ofa
When,
a=1; X=6
a=2; X=36
a=3; X=216........ Units digit repeat in a cycle of 6,6,6,6......
Similarly, Finding all values ofYfor positive values ofb
When,
b=1; Y=9
b=2; Y= 81
b=3; Y= 729....... Units digit repeat in cycle of 9,1,9,1....
So, possible value of Units digit of XY can be found by considering all possibilities of Units digit of X and Y
When X=6 and Y=9: Units digit of XY = 4
When X=6 and Y=1: Units digit of XY = 6
When X=6 and Y=9: Units digit of XY = 4
When X=6 and Y=1: Units digit of XY = 6
Only two possibilities for Units digit of XY i.e. 4 and 6.
Only 6 is given in answer choices, therefore answer is B
Question: 10 years ago, the average age of a family of 4 members was 24 years. Two children having been born (with age diference of 2 years), the present average age of the family is the same. The present age of the youngest child is :
A.1
B.2
C.3
D.4
Answer: C.3
Explanation: Explanation:
Total age of 4 members, 10 years ago = (24 x 4) years = 96 years.
Total age of 4 members now = [96 + (10 x 4)] years = 136 years.
Total age of 6 members now = (24 x 6) years = 144 years.
Sum of the ages of 2 children = (144 - 136) years = 8 years.
Let the age of the younger child be x years.
Then, age of the elder child = (X + 2)years.
So, x + (x + 2) = 8 ⇔ x = 3
Age of younger child = 3 years. Answer: C