RikoteMaster/aqua-rat-mcqa huggingface dataset:
Question: A can complete a project in 20 days and B can complete the same project in 30 days. If A and B start working on the project together and A quits 5 days before the project is completed, in how many days total will the project be completed?
A.12
B.15
C.18
D.21
Answer: B.15
Explanation: A's rate is 1/20 of the project per day.
B's rate is 1/30 of the project per day.
The combined rate is 1/12 of the project per day.
In the last 5 days, B can do 1/6 of the project.
Thus A and B must complete 5/6 of the project, which takes 10 days.
The total number of days is 10 + 5 = 15.
The answer is B.
Question: In a garden, there are 10 rows and 12 columns of mango trees. The distance between the two trees is 2 metres and a distance of one metre is left from all sides of the boundary of the garden. The length of the garden is?
A.12
B.27
C.24
D.29
Answer: C.24
Explanation: Each row contains 12 plants.
There are 11 gapes between the two corner trees (11 x 2) metres and 1 metre on each side is left.
Therefore Length = (22 + 2) m = 24 m.
Answer: C
Question: A man buys an item at Rs. 750 and sells it at the loss of 10 percent. Then what is the selling price of that item
A.Rs. 660
B.Rs. 675
C.Rs. 860
D.Rs. 960
Answer: B.Rs. 675
Explanation: Explanation:
Here always remember, when ever x% loss,
it means S.P. = (100 - x)% of C.P
when ever x% profit,
it means S.P. = (100 + x)% of C.P
So here will be (100 - x)% of C.P.
= 90% of 750
= 90/100 * 750
= 675
Option B
Question: The length, breadth and height of a room are in the ratio 7 : 4 :4. If the breadth and height are halved while the length is doubled, then the total area of the four walls of the room will
A.(a) remain the same
B.(b) decrease by 13.64%
C.(c) decrease by 27.27%
D.(d) decrease by 18.75%
Answer: C.(c) decrease by 27.27%
Explanation: Length (L) = 7
Breadth (B) = 4
Height (H) = 4
Total Area of Walls = 2(BH + LH) = 2*(4*4 + 7*4) = 2*(16+28) = 88
Then, Finally
Length (L) = 2*7 = 14
Breadth (B) = 4/2 = 2
Height (H) = 4/2 = 2
Total Area of Walls = 2(BH + LH) = 2*(2*2 + 14*2) = 2*(4+28) = 64
% change in Area of four walls = (Final Area-Initial Area)*100 /Initial Area
i.e. % change in Area of four walls = (64-88)*100 /88=- 27.27% (Decrease)
Answer: Option C
Question: A boat can move upstream at 20 kmph and downstream at 40 kmph, then the speed of the current is?
A.5
B.8
C.10
D.3
Answer: C.10
Explanation: US = 20
DS = 40
M = (40- 20)/2
= 10
Answer:C
Question: Abel can complete a work in 10 days, Ben in 14 days and Carla in 15 days. All of them began the work together, but Abel had to leave after 2 days and Ben 3 days before the completion of the work. How long did the work last?
A.6
B.7
C.7 10/29
D.9
Answer: C.7 10/29
Explanation: Abel in the 2 days that he worked completed 1/5 of the job = 4/5 remains
Then if Ben had to leave 3 days before the completion, this means that Carla had to work alone for these 3 days in which she completed 1/5 of the job.
Now together, Ben and Carla completed the job in (1/14 + 1/15)(t) = 3/5
29/210 (t) = 3/5 ---> t = 126/29
Therefore, these 4 10/29 days worked plus the 3 days that Carla had to work by herself add to 7 10/29 days
Answer: C
Question: A group of students decided to collect as many paise from each member of group as is the number of members. If the total collection amounts to Rs. 20.25, the number of the member is the group is:
A.57
B.67
C.45
D.47
Answer: C.45
Explanation: Money collected =(20.25 x 100) paise = 2025 paise
numbers of members = 2025 squareroot = 45
Answer C
Question: If xy > 0, which of the following must be negative?
A.x+y
B.x-y
C.-xy
D.-x * -y
Answer: C.-xy
Explanation: x,y must both positive or both negative. so that mn > 0 is true
positive * negative = negative
Answer : C
Question: There is enough provisions for 2400 women in an army camp for 100 days. If there were 1200 men less, how long will the provision last?
A.170
B.180
C.190
D.200
Answer: D.200
Explanation: We have, M1D1 = M2D2
2400*100= 1200* D2
D2 = 2400*100/1200 = 200 days.
ANSWER:D
Question: Sanji and Sapna start a business investing Rs.9000 each, and after 6 months, Sapna withdraws half of her capital . How should they share the profits at the end of the 24 months?
A.4:3
B.3:2
C.15:11
D.8:5
Answer: D.8:5
Explanation: Sanji invests Rs.9000 for 24 months, but Sapna invests Rs.9000 for the first 6 months and then withdraws Rs.4500. So, the investment of Sapna for remaining 18 months is Rs.4500 only.
Sanji:Sapna
9000*24 : (9000*6) + (4500*18)
216000 : 135000
Sanji:Sapna = 8:5
Answer: D
Question: A father is now three times as old as his son. Five years back, he was four times as old as his son. The age of the son (in years) is
A.12
B.15
C.18
D.20
Answer: B.15
Explanation: If father's age is F and son's age is S, then
F=3S
and
F-5 = 4*(S-5)
3S-5 =4S-20
S=15
F=45 years
ANSWER:B
Question: Find the quantities of two types of rice to be mixed, first variety is of Rs.12 per kg and second variety is of Rs.20 per kg. to get 12kg of rice mixture worth Rs.15 per kg? (in kg)
A.3.5, 8.5
B.7, 5
C.7.5, 4.5
D.8, 4
Answer: C.7.5, 4.5
Explanation: from allegation & mixture ratio=c-m/m-d=20-15/15-12=5/3.
from the option c r=7.5/4.5=5/3
ANSWER:C
Question: 3 people decided to put a down payment on a car for 3500 dollars. How much money do they each have to pay, given that that they have to pay the same amount, and they cannot use any bills below $1?
A.$1166
B.$1168
C.$1166.6
D.$1167
Answer: D.$1167
Explanation: To keep the amount exact when dividing for 3, we have to work backwards through division.
Dividing 3500 by 3 will give us 1166.66
Then by subtracting .66, we get 1166, and we multiply it by 3 to get 3498.
To get enough for the down payment, we add 3 to 3498.
Dividing the result by 3 gives us our answer.
Correct Option: D
Question: What is the scope including 1/51+1/52+1/53+......+1/60?
A.1/6~1/5
B.1/5~1/4
C.1/4~1/3
D.1/3~1/2
Answer: A.1/6~1/5
Explanation: For Maximum value : It should be less than 1/51 + 1/51 +1/51... 10 times = 10/51 ~ 1/5
For Minimum Value : It should be greater than 1/60+ 1/6+ 1/60 .. 10 times = 10/60 = 1/6.
Thus, the answer should lie between 1/6 and 1/5. Correct ans :A.
Question: A Cone, a hemisphere and a cylinder stand on equal bases and have the same height .Find ratio of their volumes.
A.2:1:3
B.2:1:4
C.1:2:3
D.4:1:7
Answer: C.1:2:3
Explanation: Let R be the radius of each
Height of the hemisphere = Its radius = R.
Height of each = R.
Ratio of volumes = (1/3)∏ R2 x R : (2/3)∏R3 : ∏ R2 x R = 1:2:3
ANSWER C 1:2:3
Question: (9^5.6x 9^10.3) ÷ 9^2.56256 = 9^?
A.11.34
B.12.34
C.13.34
D.14.34
Answer: C.13.34
Explanation: 5.6 + 10.3 = 15.9
i.e.. 15.9 - 2.56 = 13.34
so ur answer is 9^13.34
ANSWER:C
Question: In an examination, a student scores 4 marks for every correct answer and loses 1 mark for every wrong answer. If he attempts all 60 questions and secures 140 marks, the no of questions he attempts correctly is :
A.35
B.38
C.40
D.42
Answer: C.40
Explanation: Explanation:
Let the number of correct answers be X.
Number of incorrect answers = (60 – X).
4x – (60 – x) = 140
=> 5x = 200
=> x = 40
Answer: C
Question: Two trains of length 150 m and 250 m are 150 m apart. They start moving towards each other on parallel tracks, at speeds 36 kmph and 72 kmph. In how much time will the trains cross each other?
A.55/3
B.55/7
C.55/6
D.55/8
Answer: A.55/3
Explanation: Relative speed = (36 + 72)* 5/18 = 6 * 5 = 30 mps.
The time required = d/s = (150 + 150 + 250)/30
= 550/30 = 55/3 sec.
Answer: A
Question: In a fuel station the service costs $1.65 per car, every liter of fuel costs 0.65$. Assuming that a company owns 12 cars and that every fuel tank contains 55 liters and they are all empty, how much money total will it cost to fuel all cars?
A.320$
B.380$
C.420$
D.448.8$
Answer: D.448.8$
Explanation: Total Cost = ( 1.65*12 ) + ( 0.65 * 12 * 55 ) = 19.8 + 429 => 448.8
Hence answer will be (D)
Question: A man invested Rs. 1552 in a stock at 97 to obtain an income of Rs. 128. The dividend from the stock is:
A.7.5%
B.8%
C.9.7%
D.10%
Answer: B.8%
Explanation: By investing Rs. 1552, income = Rs. 128
By investing Rs. 97, income = Rs. (128/1552 * 97) = Rs. 8
Dividend = 8%
Answer = B
Question: The sides of a rectangular field are in the ratio 3 : 4. If the area of the field is 8112 sq. m, the cost of fencing the field @ 25 paise per metre is
A.Rs. 55.50
B.Rs. 67.50
C.Rs. 86.50
D.Rs. 91.00
Answer: D.Rs. 91.00
Explanation: Solution
Let length = (3x) metres and breadth = (4x) metres.
Then, 3x × 4x = 7600 ⇔ 12x2 = 8112 ⇔ x2 = 676 ⇔ x = 26
So, length = 78 m and breadth = 104 m.
Perimeter = [2(78 + 104)] m = 364 m.
∴ Cost of fencing = Rs. (0.25 × 364) = Rs. 91. Answer D
Question: A lady builds 12cm length, 16cm width, and 6cm height box using 3cubic cm cubes. What is the minimum number of cubes required to build the box?
A.345
B.384
C.378
D.398
Answer: B.384
Explanation: Number of cubes required = Volume of box/Volume of cube
= 12*16*6/3
=384 cubes
ANSWER:B
Question: In an election a candidate who gets 60% of the votes is elected by a majority of 1380 votes. What is the total number of votes polled?
A.A)4500
B.B)5200
C.C)6900
D.D)7520
Answer: C.C)6900
Explanation: Let the total number of votes polled be x
Then, votes polled by other candidate = (100-60)% of x = 40% of x
60% of x - 40% of x = 1380
20x/100 = 1380
x = 1380*100/20 = 6900
Answer is C
Question: Out of first 26 natural numbers, one number is selected at random. The probability that it is either an even number or a prime number is -.
A.1/2
B.16/19
C.4/5
D.21/26
Answer: D.21/26
Explanation: n(S) = 26
n(Even no) = 13 = n(E)
n(Prime no) = 9 = n(P)
P(EᴜP) = 13/26 + 9/26 - 1/26 = 21/26
ANSWER:D
Question: f1(x)f1(x) = 2x - 1 and fn(x)=f1(fn−1(x))fn(x)=f1(fn−1(x)) for n ≥≥ 2. Find f5(2)
A.7
B.6
C.78
D.9
Answer: A.7
Explanation: Answer:A
Question: How much interest can a person get on Rs. 8000 at 17.5% p.a. simple interest for a period of two years and six months?
A.3587.58
B.3500
C.3587.5
D.3587.52
Answer: B.3500
Explanation: I = (8000 * 2.5 * 17.5)/100 = (8000 * 5 * 35)/(100 * 2 * 2) = Rs. 3500.Answer: B
Question: Choose the missing terms out of the given alternatives.
AZ, CX, FU, ?
A.IR
B.IV
C.JQ
D.KP
Answer: C.JQ
Explanation: C
JQ
The first letter moves 2, 3, 4 ... steps forward. The second letter moves 2, 3, 4 ... steps backward.
Question: A bag contains 12 red marbles. If someone were to remove 2 marbles from the bag, one at a time, and replace the first marble after it was removed, the probability that neither marble would be red is 25/36. How many marbles are in the bag?
A.24
B.48
C.60
D.72
Answer: B.48
Explanation: ok let me see if i can explain what went on in the previous post
lets say i have x marbles in the bag in total --> out of them 12 are red
so the probability of pulling a non-red marble is (x -12) / x
now the marble is placed back in the bag and we have x marbles again, of which again 12 are red. so the probability of pulling a non-red marble out is (x-12) / x
probability theorm states that if the probability of event A occuring is m and the probability of event B occuring is n then the probability of both A and B occuring is m*n
so therefore the probability of 2 non-red marbles getting pulled out is [(x-12)/x ] * [(x-12)/x]
this is given as 25/36
-->(x-12)^2= 25/36
x^2
square rooting u have x-12/x = 5/6 or 6x-72 =5x therefore x = 72
B
Question: An oil cylinder was 3/4th full. When FOUR bottles of oil is poured into it, it is 4/5th full. How many bottles of oil
can the full cylinder hold?
A.90
B.75
C.70
D.80
Answer: D.80
Explanation: (4/5 -3/4) cylinder is filled by 4 bottles
0.8 -0.75 = 0.05 cylinder is filled by 4 bottles
1 cylinder is filled by 4/0.05 = 80 bottles
ANSWER:D
Question: In a certain neighborhood, there are half as many beige houses as white houses, and four times as many white houses as brown houses. What is the ratio of the number of brown houses to the number of beige houses?
A.1:4
B.1:2
C.1:8
D.3:2
Answer: B.1:2
Explanation: The ratio of beige:white:brown = 2:4:1
The answer is B.
Question: The below sequence is a bit tricky. Can you solve it to find the next number?
9, 29, 329, 4329, ?
A.29816
B.54329
C.54325
D.38290
Answer: B.54329
Explanation: See the pattern. With every digit, the previous numbers are added after that digit
So the next number in the series is 54329
Answer : B
Question: A boat can travel with a speed of 13 km/hr in still water.If the speed of the stream is 4 km/hr,find the time taken by the boat to go 68 km downstream.
A.2 hours
B.3 hours
C.4 hours
D.5 hours
Answer: C.4 hours
Explanation: Solution
Speed downstream = km/hr = 17 km/hr.
Time taken to travel 68 km downstream =(68/17) hrs = 4 hrs. Answer C
Question: A wire in the form of a circle of radius 3.5 m is bent in the form of a rectangule, whose length and breadth are in the ratio of 6 : 5. What is the area of the rectangle?
A.11
B.30
C.88
D.66
Answer: B.30
Explanation: The circumference of the circle is equal to the permeter of the rectangle.
Let l = 6x and b = 5x 2(6x + 5x) = 2 * 22/7 * 3.5
=> x = 1
Therefore l = 6 cm and b = 5 cm Area of the rectangle = 6 * 5 = 30 cm2
Answer:B
Question: A rectangular field is to be fenced on three sides leaving a side of 20 feet uncovered. If the area of the field is 720sq. feet, how many feet of fencing will be required?
A.34
B.92
C.68
D.88
Answer: B.92
Explanation: EXPLANATION
We have: l = 20 ft and lb = 720 sq. ft.
So, b = 36 ft.
Length of fencing = (l + 2b) = (20 + 72) ft = 92 ft.
Answer B
Question: A train 800 metres long is running at a speed of 78 km/hr. If it crosses a tunnel in 1 minute, then the length of the tunnel (in metres) is :
A.130
B.360
C.500
D.540
Answer: C.500
Explanation: Explanation:
Speed = (78 *5/18)m/sec =65/3m/sec
Time = 1 minute = 60 sec.
Let the length of the tunnel be x metres.
Then,800+X/60=65/3
=> 3 (800 + x) = 3900 =>X=500.
ANSWER IS C
Question: P and Q had the same number of candies. P gave Q 18 candies so that now Q has five times as many candies as P has. How many candies does Q have now?
A.35
B.40
C.45
D.50
Answer: C.45
Explanation: Let P and Q be the number of candies they had at the start.
P = Q
5(P-18) = Q+18
5(Q-18) = Q+18
4Q = 108
Q = 27
Now person Q has 27+18 candies which is 45 candies.
The answer is C.
Question: In a camp, food was was sufficient for 2000 people for 54 days. After 15 days, more people came and the food last only for 20 more days. How many people came?
A.1900
B.1800
C.1940
D.2000
Answer: A.1900
Explanation: Explanation :
Given that food was sufficient for 2000 people for 54 days
Hence, after 15 days, the remaining food was sufficient for 2000 people for 39 days (∵ 54 - 15 = 39)
Let x number of people came after 15 days.
Then, total number of people after 15 days = (2000 + x)
Then, the remaining food was sufficient for (2000 + x) people for 20 days
More men, Less days (Indirect Proportion)
⇒Men 2000:(2000+x)}:: 20 : 39
⇒2000 × 39 = (2000 + x)20
⇒ 100 × 39 = (2000 + x)
⇒ 3900 = 2000 + x
x = 3900 − 2000 = 1900. Answer : Option A
Question: If 1 > 1 - ab > 0, which of the following must be true?
I. a/b > 1
II. a/b > 0
III. ab < 1
A.I only
B.II only
C.III only
D.II and III only
Answer: D.II and III only
Explanation: MANHATTAN GMATOFFICIAL SOLUTION:
You can manipulate the original compound inequality as follows, making sure to perform each manipulation on every term:
1 > 1 - ab > 0
0 > -a b > -1 Subtract 1 from all three terms.
0 < ab < 1 Multiply all three terms by -1 and flip the inequality signs.
Therefore you know that 0 < ab < 1. This tells you that ab is positive, so a/b must be positive (a and b have the same sign). Therefore, I must be true. However, you do not know whether a/b < 1, so II is not necessarily true. But you do know that ab must be less than 1, so III must be true.
Therefore, the correct answer is (D).
Question: A train passes a platform in 30 seconds. The same train passes a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr, The length of the platform is
A.150 meter
B.240 meter
C.200 meter
D.260 meter
Answer: A.150 meter
Explanation: Explanation:
Speed of the train = 54 km/hr = (54×10)/30 m/s = 15 m/s
Length of the train = speed × time taken to cross the man = 15×20 = 300 m
Let the length of the platform = L
Time taken to cross the platform = (300+L)/15
=> (300+L)/15 = 30
=> 300+L = 15×30 = 450
=> L = 450-300 = 150 meter
Answer: Option A
Question: If 1 + x^4 + x^3 + x^2 + x = 80, then the average (arithmetic mean)Y of x, x^2, x^3, x^4 and x^5 is equal to which of the following?
A.12x
B.13x
C.14x
D.16x
Answer: D.16x
Explanation: 1 + x^4 + x^3 + x^2 + x = 81
i.e. 1 +x+ x^2+ x^3+ x^4 = 81
x+ x^2+ x^3+ x^4 = 80
x(1 +x+ x^2+ x^3) = 80
x(81-x^4) = 80
81x - x^5 = 80
x^5 = 81x -80
Now x+ x^2+ x^3+ x^4+ x^5 = 80 + 81x -80 = 81x
Average of Y{x, x^2, x^3, x^4, x^5} = 81x/5 ~ 16x
AnswerD
Question: Two numbers N and 14 have LCM = 56 and GCF = 12. Find N.
A.48
B.34
C.44
D.54
Answer: A.48
Explanation: The product of two integers is equal to the product of their LCM and GCF. Hence.
14 × N = 56 × 12
N = 56 × 12 / 14 = 48
correct answer A
Question: The membership of a committee consists of 3 science teachers, 4 Mathematics teachers, and 2 Social Studies teachers. If 2 committee members are to be selected at random to write the committee’s report, what is the probability that the two members selected will both be science teachers?
A.1/12
B.1/3
C.2/9
D.1/14
Answer: A.1/12
Explanation: Probability of first member an science teacher = 3/9
Probability of second member an science teacher = 2/8
Probability of both being english teacher = 3/9 x 2/8 =1/12 (A)
Question: A shopkeeper fixes the marked price of an item 30% above its cost price. The percentage of discount allowed to gain 8% is
A.15.92%
B.16.92%
C.17.92%
D.18.92%
Answer: B.16.92%
Explanation: Explanation:
Let the cost price = Rs 100
then, Marked price = Rs 130
Required gain = 8%,
So Selling price = Rs 108
Discount = 130 - 108 = 22
Discount% = (22/130)*100 = 16.92%
Option B
Question: If the dimensions of a certain rectangular box are 5 inches by 2 inches by 3 inches, then the face of greatest area is of what area?
A.225 square inches
B.45 square inches
C.25 square inches
D.15 square inches
Answer: D.15 square inches
Explanation: Definitely (D) 5*3 = 15 sq Inches
The question asks to find the greatest area of the faces of a cuboid
The Possible area of the faces are -
Length*Breadth , Breadth*Height & Height*Length
The possible areas are - 6 , 10 & 15
Thus 15 is the greatest possible area....
ANSWER:D
Question: If the number 24*32 is completely divided by 6. what is the smallest whole number in the place of * ?
A.4
B.3
C.1
D.2
Answer: C.1
Explanation: Solution
The number is divisible by 6 means it must be divisible by 2 and 3. Since the number has 2 as its end digit it is divisible by 2. Now, 2+4+x+3+2=11+x which must be divisible by 3. Thus x=1
Answer C
Question: Maxwell leaves his home and walks toward Brad's house at the same time that Brad leaves his home and runs toward Maxwell's house. If the distance between their homes is 20 kilometers, Maxwell's walking speed is 4 km/h, and Brad's running speed is 6 km/h, what is the distance traveled by Brad?
A. 12
B. 18
C. 20
D. 24
Answer: A. 12
Explanation: Time taken = Total Distance / Relative Speed
Total Distance = 20 kms
Relative Speed (Opposite side) (As they are moving towards each other speed would be added ) = 6+ 4 = 10 kms/hr
Time taken = 20 / 10 = 2 hrs
Distance traveled by Brad = Brad's speed * time taken = 6 * 2 = 12 kms... Answer - A
Question: An inspector rejects 0.00008% of the meters as defective. How many will be examine to project ?
A.2000
B.2300000
C.2700
D.2500000
Answer: D.2500000
Explanation: Let the number of meters to be examined be x.
Then, 0.00008% of x =2
[(8/100000)*(1/100)*x] = 2
x = [(2*100000*100)/8] = 2500000
Answer is D.
Question: Perimeter of front wheel =30, back wheel = 20. If front wheel revolves 240 times. How many revolutions will the back wheel take?
A.120
B.180
C.240
D.360
Answer: D.360
Explanation: sice the distance covered by both the wheels should be same
so
let x be the no. of revolutions by the back wheel
so 240*2*pie*30=x*2*pie*20
so x=360.
ANSWER:D
Question: The sum of the smallest six digit number and the greatest five digit number is
A.201110
B.199999
C.211110
D.1099999
Answer: B.199999
Explanation: Solution
Requires sum	=(100000 + 99999)
=199999.
Answer B
Question: if a * b = 2a – 3b + ab, then 3 * 5 + 5 * 3 is equal to :
A.22
B.24
C.26
D.28
Answer: A.22
Explanation: Solution
3 × 5 + 5 ×3 = (2 ×3 - 3 × 5 + 3 × 5) + 2 (2 × 5 - 3 × 3 +5 × 3)
= (6 + 10 - 9 + 15) = 22.
Answer A
Question: There is a soccer tournament that is single elimination meaning that after one loss the team is out. There are 15 teams in this tournament. How many games are played?
A.15
B.7
C.8
D.14
Answer: D.14
Explanation: D
The number of games always adds up to one less than the number of teams in a single elimination tournament. You may calculate it any way. Therefore, 14 games were played.
Question: The sum of the present ages of a father and his son is 60 years. five years ago, father's age was four times the age of the son. so now the son's age will be:
A.5
B.10
C.15
D.20
Answer: C.15
Explanation: Explanation:
Let the present ages of son and father be x and (60 -x) years respectively.
Then, (60 - x) - 5= 4(x - 5)
55 - x = 4x - 20
5x = 75 x = 15. Answer: C
Question: In how many seconds will a train 100 meters long pass an oak tree, if the speed of the train is 36 km/hr?
A.6
B.8
C.10
D.12
Answer: C.10
Explanation: speed = 36 * 5/18 = 10 m/s
time = 100/10 = 10 seconds
The answer is C.
Question: What positive number, when squared, is equal to the cube of the positive square root of 15?
A.64
B.32
C.8
D.6
Answer: D.6
Explanation: Let the positive number be x
x^2 = ((15)^(1/2))^3
=>x^2 = 4^3 = 36
=> x = 6
Answer D
Question: Find the amount on Rs.8000 in 2 years, the rate of interest being 4% per first year and 5% for the second year?
A.5568
B.6369
C.8736
D.5635
Answer: C.8736
Explanation: 8000 * 104/100 * 105/100
=> 8736
Answer:C
Question: If 16 toys cost 240, then what do 40 toys cost ?
A.Rs. 600
B.Rs. 620
C.Rs. 640
D.Rs. 660
Answer: C.Rs. 640
Explanation: Explanation:
Although we can first calculate the cost of one toy and then can multiply it with 40 to get the result.
but we will solve it with chain rule so that we can prepare ourself for other complex problems which we can solve easily by applying this rule.
Let the required cost be Rs. x
More toys means More Cost. (Direct Proportion)
15:40::240:x=>x=240∗40/15=>x=640
So 40 toys will cost Rs 640
Option C
Question: Of the three numbers, the sum of the first two is 45; the sum of the second and the third is 55 and the sum of the third and thrice the first is 90. The third number is
A.15
B.20
C.25
D.30
Answer: D.30
Explanation: Sol.
Let the numbers be x,y and z.
Then, x + y = 45
y+z = 55 and
3x+z = 90
⇒ y = 45 - x, z = 55 - y = 55 - (45 - x) = 10 + x.
∴ 3x + 10 + x = 90 or x = 20.
y = (45 - 20) = 25 and z = (10 + 20) = 30.
∴ Third number = 30.
Answer D
Question: A tank is filled in 5 hours by three pipes A, B and C. The pipe C is twice as fast as B and B is twice as fast as A. How much time will pipe A alone take to fill the tank?
A.35 hours
B.25 hours
C.20 hours
D.Cannot be determined
Answer: A.35 hours
Explanation: Suppose the efficiencies of pipes C, B and A are 4K, 2K and K.
Since, the tank is filled in 5 hours by the three pipes having combined efficiency equal to 7K, the time required to fill the tank by A alone = 7K×5 /K=35hours
Answer A
Question: If X = 2 + 1/(1+1/(1-1/2))then the value of 4x+7/3?
A.9 2/3
B.10 1/3
C.11
D.11 2/3
Answer: D.11 2/3
Explanation: X = 2 + 1/(1+1/(1-1/2))
= 2 + 1/(1+2)
= 2 + 1/3
X = 7/3 ==> 4X + 7/3 => 4(7/3) + 7/3
==> 28/3 + 7/3
==> 35/3
==> 11 2/3.
D)