RikoteMaster/aqua-rat-mcqa huggingface dataset:
Question: How many times the keys of a writer have to be pressed in order to write first 250 counting no's?
A.632
B.642
C.652
D.662
Answer: B.642
Explanation: 1 to 9 = 9 * 1 = 9
10 to 99 = 90 * 2 = 180
100 to 250 = 151 * 3 = 453
-----------
642
B
Question: Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is?
A.3/8
B.3/2
C.3/5
D.3/6
Answer: B.3/2
Explanation: Let the speeds of the two trains be x m/sec and y m/sec respectively. Then, length of the first train
= 27 x meters, and length of the second train = 17 y meters. (27 x + 17 y) / (x + y) = 23
==> 27 x + 17 y
= 23 x + 23 y
==> 4 x = 6 y
==> x/y
= 3/2.
Answer: B
Question: Raju age after 45 years will be 5 times his age 5 years back, What is the present age of Raju
A.28.5
B.17.2
C.10.2
D.17.5
Answer: D.17.5
Explanation: Clearly,
x+45 = 5(x-5)
<=> 4x = 70 => x = 17.5
Answer:D
Question: The output of a factory is increased by 10% to keep up with rising demand. To handle the holiday rush, this new output is increased by 60%. By approximately what percent would the output of the factory now have to be decreased in order to restore the original output?
A.20%
B.24%
C.30%
D.43%
Answer: D.43%
Explanation: take it as original output =100.
to meet demand increase by 10%, then output=110.
to meet holiday demand , new output increase by 60% then output equals 176
To restore new holidy demand output to original 100.
final -initial/final*100
=76/176*100=8/33*100=43% approxiamately.
option D is correct.
Question: The value of 4.5*1.8+4.5*8.2/1.5*4.5+1.5*5.5
A.7
B.8
C.5
D.3
Answer: D.3
Explanation: Exp: 4.5*1.8+4.5*8.2/1.5*4.5+1.5*5.5 = 4.5 (1.8+8.2)/1.5 (4.5+5.5)
= 4.5*10/1.5*10
= 45/15 =3
ANSWER:D
Question: What is the remainder when 5632 is divided by 6?
A.2
B.1
C.0
D.4
Answer: A.2
Explanation: f the number is divisible by both 2 and 3, then number will be divisible by 6.
As there is 2 an even number in units place it is divisible by 2.
sum of digits is:5+6+3+2=16. 16 is not divisible by 3 hence number is not divisible by 3.
The nearest multiple of 6 is 5630.
5632-5630=2.
Answer:2
Question: The cost to park a car in a certain parking garage is $20.00 for up to 2 hours of parking and $1.75 for each hour in excess of 2 hours. What is the average (arithmetic mean) cost per hour to park a car in the parking garage for 9 hours?
A. $3.58
B. $1.67
C. $2.25
D. $2.37
Answer: A. $3.58
Explanation: Total cost of parking for 9 hours = 20$ for the first 2 hours and then 1.75 for (9-2) hours = 20+7*1.75 = 32.25
Thus the AVERAGE parking price = 32.25/9 = 3.58 $
A is the correct answer.
Question: For dinner at a restaurant, there are x choices of appetizers, y + 1 main courses, and z+1 choices of dessert. How many total possible choices are there if you choose 1 appetizer, 1 main course, and 1 dessert for your meal?
A.x + y + z + 1
B.xyz + xz
C.xy + z + 1
D.xz+x+xyz+xy
Answer: D.xz+x+xyz+xy
Explanation: x appetizers,
y + 1 main courses,
z+1 dessert
Required: 1 appetizer, 1 main course, and 1 dessert
Number of ways possible = xC1*(y+1)C1*(z+1)C1 {NC1 = N! / (N-1)!*1! = N}
Hence, number of ways = x(y+1)(z+1) = (x + xy)(z+1)=xz+x+xyz+xy
Correct Option: D
Question: A company has two types of machines, type R and type S. Operating at a constant rate a machine of R does a certain job in 36 hours and a machine of type S does the job in 36 hours. If the company used the same number of each type of machine to do job in 12 hours,how many machine R were used?
A.3
B.4
C.6
D.9
Answer: D.9
Explanation: yes there is a typo in the question, I got the same ques on my GMAT PREP last week, and the questions goes as:
A company has two types of machines,type R and type S.Operating at a constant rate a machine of R does a certain job in 36 hours and a machine of type S does the job in 36 hours .If the company used the same number of each type of machine to do job in2 hours,how many machine R were used?
So for a job to be done in 2 hours R = 1/2
R_a(Rate of Machine R) = 1/36
R_s(Rate of Machine S) = 1/36
Lets say x machines are used to attain the desired rate, thus
x/36+x/36 = 1/2 (Desired R =1/2 i.e. to complete the job in 2 hours)
(x+x)/36 = 1/2
2x/36 = 1/2
x = 9.
QA = 9 (ANSWER D)
Question: A trumpet section includes five musicians. If they hold an audition to determine chair order within the section, and there are to be no ties, how many distinct chair orders can result?
A.240
B.125
C.120
D.100
Answer: C.120
Explanation: We have a word problem using permutations. We must identify the number of total items in the group. There are five possible musicians who could be placed in the first chair, four possible musicians for the second, three for the third, two for the fourth, and one for the fifth. To determine the number of possible orderings, we multiply these numbers, which we can express as 5!. Now 5! = (5)(4)(3)(2)(1) = 120.
ANS:C
Question: There are four temples, one plant of flower and a pond.
A boy goes there and before entering the first temple he plucks the flower and has to take a bath in the pond before entering into every temple.
The specialty of the pond is that if a person is carrying flowers with him and he takes a dip in the pond the number of the flowers gets doubled.
He takes a dip and offers some flowers in the first temple, then he again takes a dip and offers flowers in second temple , again the same in the third temple, and again the same in the fourth temple
The boy offers EQUAL number of flowers in all the four temples and goes back with EMPTY hand after offering flower in the fourth temple..How many flowers could he have offered in each temples?
A.20
B.24
C.30
D.48
Answer: D.48
Explanation: Note : all temples received equal flowers
lets start with the 4th temple , lets say all x flowers were given, then before dip x/2 flowers must have been left after offering in the 3rd temple. ( only then x/2 flowers could be doubled to become x and all offered in the 4th temple with nothing left over )
so x/2 flowers were left after offering made in the 3rd temple
going backwards .....
(x/2) left after 3rd temple + x given in the 3rd temple =(3x/2) {after dip, total flowers just before offering in the 3rd temple}
so before dip (3x/4)
(3x)/4 left after 2nd temple + x given in the 2nd temple = (7x)/4{after dip, total flowers just before offering in the 2nd temple}
so before dip (7x)/8
(7x)/8 left after 1st temple + x given in the 1st temple = (15x)/8{after dip, total flowers just before offering in the 1st temple}
so before dip (15x)/16
now since number of flowers have to be an integer then x has to be a multiple of 2,4,8 and 16
only 48 satisfies
Hence Answer = D
Question: How many times are the hands of a clock at right angle in 5 days?
A.202
B.220
C.210
D.212
Answer: B.220
Explanation: In 1 day, they are at right angles 44 times.
In 5 days, they are at right angles 220 times. Answer: Option B
Question: 10 men and 15 women together can complete a work in 4 days. It takes 100 days for one man alone to complete the same work. How many days will be required for one woman alone to complete the same work?
A.100 days
B.667 days
C.177 days
D.187 days
Answer: A.100 days
Explanation: 1 man's 1 day work = 1/100
(10 men + 15 women)'s 1 day work = 1/4
15 women's 1 day work = (1/4 - 10/100) = 3/20
1 woman's 1 day work = 1/100
1 woman alone can complete the work in 100 days.
Answer:A
Question: A box contains nine bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that exactly three bulbs are good?
A.20/66
B.20/63
C.20/87
D.20/98
Answer: B.20/63
Explanation: Required probability = (5C3 . 4C1)/9C4
= (10 * 4)/126
= 20/63
Answer:B
Question: Two cars are traveling towards each other. If car A is traveling at a speed of 50 mph and car B is traveling 12% slower, how much time will it take the cars to meet if the initial distance between the two is 705 miles?
A.Six hours and 30 minutes.
B.Seven hours and 30 minutes.
C.Eight hours and 20 minutes.
D.Nine hours and 15 minutes.
Answer: B.Seven hours and 30 minutes.
Explanation: since they are travelling towards each other, the total speed is 50 mph + 50*0.88 = 94 mph (0.88 since, the other car is 12% less than first one)
Distance to be covered is 705, so time taken = distance/speed = 705/94 = 7.5 hours or 7 hours and 30 mins.
Answer is B: Seven hours and 30 minutes.
Question: Of 70 players on a football team, 34 are throwers. The rest of the team is divided so one third are left- handed and the rest are right handed. Assuming that all throwers are right handed, how many right- handed players are there total?
A.54
B.58
C.63
D.71
Answer: B.58
Explanation: Total = 70
Thrower = 34
Rest = 70 - 34 = 36
Left Handed = 36/3 = 12
Right handed = 24
If all Thrower are right handed then total right handed is 34 + 24 = 58
so B. 58 is the right answer
Question: If
1 = 6
2 = 12
3 = 18
4 = 24
5 = 30
6 = 36
Then 12 = ?
Hint: Its a logic Riddle not a mathematical riddle
A.1
B.2
C.3
D.4
Answer: B.2
Explanation: B
2
As stated
2=12 => 12=2
Answer is B
Question: What will come in place of the x in the following Number series? 18, 22, 30, x ,78, 142
A.26
B.32
C.46
D.49
Answer: C.46
Explanation: (C)
The pattern is +4, +8, +16, +32, +64
So the missing term is = 30 + 16 = 46 .
Question: The area of a rectangle is 360 Sq.m. If its length is increased by 10m and its width is decreased by 6m, then its area does not change. Find the perimeter of the original rectangle.
A.74m
B.75m
C.76m
D.77m
Answer: C.76m
Explanation: let l and b are the length and width of the original rectangle.
since,l*b=360sq.m-(1)
now,a/c to the problem
(l+10)*(b-6)=360sq.m
therefore,
b=6(1+l/10)-(2)
l*l+10l-600=0 {by using equations 1 and 2}
thereafter,
(l-20)(l+30)=0
hence, l=20m
b=18m {by using equation 2}
now, Perimeter of the original rectangle=2(l+b)=2(20+18)=76m
ANSWER:C
Question: A shopkeeper sells 400 metres of cloth for Rs. 18000 at a loss of Rs.5 per metre. Find his cost price for one metre of cloth?
A.12
B.67
C.26
D.50
Answer: D.50
Explanation: SP per metre = 18000/400 = Rs. 45 Loss per metre = Rs. 5 CP per metre = 45 + 5
= Rs. 50
Answer:D
Question: Rs.8000 become Rs.9261 in a certain interval of time at the rate of 5% per annum of C.I. Find the time?
A.6 years
B.8 years
C.9 years
D.3 years
Answer: D.3 years
Explanation: 9261 = 8000(21/20)N
(21/20)3 = (21/20)N => N = 3
5. At the end of three years what will be the comp.Answer: OD
Question: In how many ways can three boys and three girls sit in a row such that all girls sit together?
A.A)160
B.B)144
C.C)96
D.D)120
Answer: B.B)144
Explanation: Treat all girls as one unit. Now there are four students and they can be arranged in 4! ways. Again three girls can be arranged among themselves in 3! ways.
Required number of arrangements
= 4! * 3! = 24 * 6
= 144.
Answer:B
Question: A shopkeeper sells 20% of his stock at 10% loss ans sells the remaining at a profit of 10%. He incurred an overall profit of Rs. 1500. Find the total worth of the stock?
A.27500
B.26000
C.24000
D.25000
Answer: D.25000
Explanation: Let the total worth of the stock be Rs. x.
The SP of 20% of the stock = 1/5 * x * 9/10 = 9x/50
The SP of 80% of the stock = 4/5 * x * 1.1 = 44x/50
Total SP = 9x/50 + 44x/50 = 53x/50
Overall profit = 53x/50 - x = 3x/50
3x/50 = 1500 => x = 25000
Answer:D
Question: Peter’s salary is reduced by 30% and then reduced salary is increased by 30%. Find ,how many percentage his present salary is less as compared to his previous salary?
A.6%
B.7%
C.8%
D.9%
Answer: D.9%
Explanation: 30*30
-------- = 9%
100
Answer: D
Question: Thomas went to a shop and bought things worth Rs. 25, out of which 30 Paise went on sales tax on taxable purchases. If the tax rate was 6%, then what was the cost of the tax free items?
A.19.7
B.20
C.20.1
D.21.3
Answer: A.19.7
Explanation: Total cost of the items he purchased = Rs.25
Given that out of this Rs.25, 30 Paise is given as tax
=> Total tax incurred = 30 Paise = Rs.30/100
Let the cost of the tax free items = x
Given that tax rate = 6%
∴ (25−30/100−x)6/100 = 30/100
⇒ 6(25 −0.3 −x) = 30
⇒ (25 − 0.3 − x) = 5
⇒ x = 25 − 0.3 − 5 = 19.7
A)
Question: In a certain game, a large container is filled with red, yellow, green, and blue beads worth, respectively, 7, 5, 3, and 2 points each. A number of beads are then removed from the container. If the product of the point values of the removed beads is 1,029,000, how many red beads were removed?
A.5
B.4
C.3
D.2
Answer: C.3
Explanation: 1,029,000
= 2^3 * 5^3 * 1029
= 2^3 * 3 * 5^3 * 343
= 2^3 * 3 * 5^3 * 7^3
The answer is C.
Question: Two numbers are in the ratio 3:5. If 9 be subtracted from each, they are in the ratio of 5:2. The first number is:
A.A)3
B.B)98
C.C)34
D.D)35
Answer: A.A)3
Explanation: (3x-9):(5x-9) = 5:2
x = 1 => 3x = 3
Answer:A
Question: A father purchased dress for his 3 daughters. The dresses are of same color but diff size and they are kept in dark room. what is probability that all the 3 will not choose there own dress?
A.1/3
B.2/3
C.1/2
D.3/4
Answer: A.1/3
Explanation: Explanation :
Let 1st girl come and she choose wrong dress so probability of that girl to choose wrong dress out of
3 is =2/3.
Now 2nd girl come nd she choose wrong dress so probability of that girl to choose wrong dress out of
2 is 1/2.
Now for 3rd girl probability is 1 to choose wrong dress.
So probability tht all the 3 wil not choose der own dress is = 2/3 * 1/2 * 1 = 1/3.
Hence (A) is the correct answer.
Answer : A
Question: What percent is 5 gm of 1 kg?
A.1.5 %
B.0.5 %
C.2.5 %
D.3.5 %
Answer: B.0.5 %
Explanation: 1 kg = 1000 gm
5/1000 × 100 = 500/1000
=1/2 = 0.5 %
B)
Question: A boat can travel with a speed of 22 km/hr in still water. If the speed of the stream is 5 km/hr, find the time taken by the boat to go 81 km downstream
A.5 hours
B.4 hours
C.3 hours
D.2 hours
Answer: C.3 hours
Explanation: Explanation :
Speed of the boat in still water = 22 km/hr
speed of the stream = 5 km/hr
Speed downstream = (22+5) = 27 km/hr
Distance travelled downstream = 81 km
Time taken = distance/speed = 81/27 = 3 hours. Answer : Option C
Question: The average number of shirts with Salman, Ambani and Dalmiya is 72, if all of them reached a shopping mall in Delhi and purchased 12 shirts each of them then average number of shirt each of them now has
A.84
B.87
C.86
D.can't be determined
Answer: A.84
Explanation: Answer
Required average
= Old average + New average
= 72 + 12 = 84
Correct Option: A
Question: A committee is to be formed by randomly choosing 3 people from 8 candidates. If Alice and Bob are candidates, what is the probability that Alice will be selected but Bob will not?
A.3/7
B.9/28
C.11/28
D.15/56
Answer: D.15/56
Explanation: The total number of ways to form a committee is 8C3=56.
The number of committees which include Alice but not Bob is 6C2=15.
The probability that Alice is selected but Bob is not selected is 15/56.
The answer is D.
Question: If x and y are two-digit integers such that x > 30 and y<70, which of the following is closest to the minimum value of xy?
A. 700
B. 460
C. 4,000
D. 310
Answer: D. 310
Explanation: To get the minimum possible value of xy, we need minimize the value of both x and y
min x can be = 31 (given x is a two-digit integer > 30)
min y can be = 10 (given y is a two-digit integer < 70)
xy = 31*10 = 310
Answer (D)
Question: There is enough provisions for 600 men in an army camp for 25 days. If there were 200 men less, how long will the provision last?
A.50days
B.60days
C.70days
D.75days
Answer: D.75days
Explanation: Exp: We have, M1D1 = M2D2
600*25= 200* D2
D2 = 600*25/200 = 75 days.
Answer: D
Question: 0.05 x 0.40=?
A.3.15e-05
B.0.000315
C.0.315
D.0.02
Answer: D.0.02
Explanation: 5 x 40 = 200
Sum of decimal places =4
Therefore, 0.05x 0.44 = 0.0200
Answer is D.
Question: The total marks obtained by a student in Mathematics and Physics is 30 and his score in Chemistry is 20 marks more than that in Physics. Find the average marks scored in Mathamatics and Chemistry together.
A.40
B.30
C.25
D.Data inadequate
Answer: C.25
Explanation: Let the marks obtained by the student in Mathematics, Physics and Chemistry be M, P and C respectively.
Given , M + C = 30 and C - P = 20 M + C / 2 = [(M + P) + (C - P)] / 2 = (30 + 20) / 2 = 25.
ANSWER:C
Question: 42, 40, 35, 33, 28, 26, ?
A.21
B.23
C.28
D.25
Answer: A.21
Explanation: This is a simple alternating subtraction series, with a pattern -2, -5, -2, -5, -2 ....
Answer : A.
Question: Find the sum The difference between the compound and S.I. on a certain sum of money for 2 years at 10% per annum is Rs.15of money?
A.1500
B.2887
C.2668
D.2977
Answer: A.1500
Explanation: P = 15(100/10)2 => P = 1500.Answer: A
Question: Susan weighs 12 pounds more than Anna does, and together they weigh a total of 162 pounds. Which of the following represents Anna’s weight in pounds?
A.70
B.75
C.65
D.68
Answer: B.75
Explanation: Total weight = 162
Anna's weight = 162-12 /2 = 75
Answer : B
Question: You collect balls. Suppose you start out with 106. Your sister gives you another 17 balls. How many balls do you have at the end?
A.106
B.17
C.321
D.123
Answer: D.123
Explanation: Solution
Start with 106 balls.
Sister gives you 17 balls: 106 + 17 = 123 balls.
So you have 123 at the end.
Correct answer: D
Question: A bag of potatoes weighs 50 lbs divided by half of its weight. How much does the bag of potatoes weigh?
A.10 lb
B.20 lb
C.30 lb
D.40 lb
Answer: A.10 lb
Explanation: A
10 lb
50÷5 = 10.
Question: Angelo and Isabella are both salespersons. In any given week, Angelo makes $550 in base salary plus 8 percent of the portion of his sales above $3,000 for that week. Isabella makes 10 percent of her total sales for any given week. For what amount of weekly sales would Angelo and Isabella earn the same amount of money?
A. 23,500
B. 15,500
C. 25,500
D. 26,500
Answer: B. 15,500
Explanation: OFFICIAL SOLUTION:
The problem asks for the amount of weekly sales it takes for Angelo and Isabella to earn the same amount of money. You can write an equation that sets Angelo’s and Isabella’s weekly earnings equal to each other, with x representing weekly sales. Weekly earnings for each salesperson equal base salary plus commission. So Angelo’s earnings are 550 + (0.08)(x – 3,000), and Isabella’s are 0.10x. Set up the equation and solve:
550 + (0.08)(x – 3,000) = 0.10x
Distribute the 0.08:
550 + 0.08x – 240 = 0.10x
Combine terms and subtract 0.08x from both sides:
310 = 0.02x
Divide both sides by 0.02:
15,500 = x
Your answer is B.
Question: If a number is chosen at random from the set {1, 2, 3…, 100}, then the probability that the chosen number is a perfect cube is
A.1/25
B.1/2
C.4/13
D.1/10
Answer: A.1/25
Explanation: We have 1, 8, 27 and 64 as perfect cubes from 1 to 100. Thus, the probability of picking a perfect cube is 4/100 = 1/25
ANSWER:A
Question: The sides AB,BC and CA of a triangle ABC having 3,4 and 5 interior points receptively on them. The total number of triangles that can be constructed by using these points as vertices is
A.220
B.204
C.205
D.195
Answer: C.205
Explanation: (3C1*4C1*5C1)+(3C2*4C1)+(3C2*5C1)+(4C2*3C1)+(4C2*5C1)+(5C2*3C1)+(5C2*4C1)
=60+12+15+18+30+30+40
=205
ANSWER:C
Question: Average age of students of an adult school is 48 years. 120 new students whose average age is 32 years joined the school. As a result the average age is decreased by 4 years. Find the number of students of the school after joining of the new students.
A.1200
B.160
C.360
D.240
Answer: B.160
Explanation: Explanation :
Let the original no. of students be x.
According to situation, 48x + 120*32 = (x + 120)36 ⇒ x = 40
So, Required no. of students after joining the new students
= x + 120 = 160.
Answer : B
Question: There are 34 students in a certain geometry class. If two thirds of the students are boys and three fourths of the boys are under six feet tall, how many boys in the class are under six feet tall?
A.6
B.12
C.17
D.24
Answer: C.17
Explanation: 34*2/3 *3/4= 17
Answer: C
Question: The length of each side of an equilateral triangle having an area of 4√3 cm2 is?
A.3:4
B.3:9
C.3:7
D.3:1
Answer: A.3:4
Explanation: Let the speed of the train be x km/hr and that of the car be y km/hr.
Then, 120/x + 480/y = 8 or 1/x + 4/y = 1/15 --- (i)
And, 200/x + 400/y = 25/3 or 1/x + 2/y = 1/24 --- (ii)
Solving (i) and (ii), we get x = 60 and y = 80
Ratio of speeds = 60:80
= 3:4
Answer:A
Question: The present ages of three persons are in proportions 4:7:9. Eight years ago, the sum of their ages was 56. Find their present ages.
A.8, 20, 28
B.16, 28, 36
C.20, 35, 45
D.20, 35, 55
Answer: B.16, 28, 36
Explanation: Let their present ages be 4x, 7x and 9x years respectively.
Then, (4x - 8) + (7x - 8) + (9x - 8) = 56
20x = 80 => x = 4
Their present ages are 16, 28 and 36 years respectively.
ANSWER:B
Question: 3 houses are available in a new flat. 3 persons apply for the houses. Each applies for 1 house without consulting others.The probability that all the 3apply for the same house is?
A.1/7
B.1/9
C.2/7
D.3/7
Answer: B.1/9
Explanation: One person can select one house out of 3= \inline {\color{Black}3C_{1}} ways =3.
Hence, three persons can select one house out of 3 in 3 x 3 x 3 =9.
Therefore, probability that all thre apply for the same house is 1/9
B
Question: The angles of a triangle are in the ratio 1 : 3 : 8. Find the measurement of the 3angles of triangle.
A.100°
B.110°
C.120°
D.180°
Answer: C.120°
Explanation: If the ratio of the three angles is 1:3:8, then the measures of these angles can be written as x, 3x and 8x. Also the sum of the three interior angles of a triangle is equal to 180°. Hence
x + 3x + 8x = 180
Solve for x
12x = 180
x = 15
The measures of the three angles are
x = 15°
3x = 3 × 15 = 45°
8x = 8 × 15 = 120°
C
Question: Last year’s receipts from the sale of greeting cards during the week before Mother’s Day totaled $194 million, which represented 8 percent of total greeting card sales for the year. Total greeting card sales for the year totaled how many million dollars?
A.17,010
B.2,100
C.2425
D.2564
Answer: C.2425
Explanation: 8% ---- 194 millions
for 100% => ( 194 * 100% )/8% = 2425.
Option C
Question: A perfect square is defined as the square of an integer and a perfect cube is defined as the cube of an integer. How many positive integers n are there such that n is less than 100,000 and at the same time n is a perfect square and a perfect cube?
A.3
B.4
C.5
D.6
Answer: D.6
Explanation: If n is a perfect square and a perfect cube, then n = a^6 for some integer a.
The numbers are 1^6=1, 2^6=64, 3^6= 729, 4^6=4096, 5^6=15,625, 6^=46,656.
The answer is D.
Question: if x:y = 1:7, then find the value of
(7x+3y):(2x+y)
A.14:5
B.15:5
C.28:9
D.17:5
Answer: C.28:9
Explanation: Explanation:
let x = 1k and y = 7k, so
=7(k)+3(7k)/ 2(k)+1(7k)
=28k/9k
=28:9
Option C
Question: Pipes A and B can fill a tank in 2 and 3 hours. Pipe C can empty it in 6 hours. If all pipes are opened together, then the tank will be filled in?
A.3/2hr
B.1/2hr
C.1hr
D.9/7hr
Answer: B.1/2hr
Explanation: Net part filled in 1 hour = 1/2 + 1/3 - 1/6 = 2/3
The tank will be full in 3/2 hr
Answer is B
Question: A box contains 4 red, 3 white and 2 blue balls. Three balls are drawn at random. Find out the number of ways of selecting the balls of different colours
A.12
B.24
C.48
D.168
Answer: B.24
Explanation: Explanation:
This question seems to be a bit typical, isn't, but it is simplest.
1 red ball can be selected in 4C1 ways
1 white ball can be selected in 3C1 ways
1 blue ball can be selected in 2C1 ways
Total number of ways
= 4C1 x 3C1 x 2C1
= 4 x 3 x 2
= 24
Please note that we have multiplied the combination results, we use to add when their is OR condition, and we use to multiply when there is AND condition, In this question it is AND as
1 red AND 1 White AND 1 Blue, so we multiplied.
Option B
Question: A, B and C play a cricket match. The ratio of the runs scored by them in the match is A:B = 2:3 and B:C = 2:5. If the total runs scored by all of them are 75, the runs scored by B are?
A.23
B.18
C.20
D.19
Answer: B.18
Explanation: Answer: Option B
a:b = 2:3
b:c = 2:5
a:b:c = 4:6:15
6/25 * 75 = 18
Question: The speed of a boat in still water is 50kmph and the speed of the current is 20kmph. Find the speed and upstream?
A.30 kmph
B.40 kmph
C.78 kmph
D.15 kmph
Answer: A.30 kmph
Explanation: Speed downstream = 50 + 20 = 70 kmph
Speed upstream = 50 - 20 = 30 kmph
Answer:A