AMCAT Quantitative Ability: Applied Mathematics 2

Question 1

A pipe can fill a tank in 12 hours and another pipe can empty it in 18 hours. If both are opened simultaneously, in how many hours will the tank be filled?

Accepted Answer

36 hours

Answer

Fill rate = 1/12 per hour. Empty rate = 1/18 per hour. Net fill rate = 1/12 – 1/18 = 1/36. Time = 36 hours.

Question 2

A train travels at 60 km/h for the first half of the distance and 90 km/h for the second half. What is the average speed?

Accepted Answer

72 km/h

Answer

Average speed for equal distances = 2v1v2/(v1+v2) = 2×60×90/150 = 72 km/h.

Question 3

The ages of A and B are in ratio 5:3. After 6 years the ratio becomes 7:5. What is A's current age?

Accepted Answer

15 years

Answer

Let A=5x, B=3x. (5x+6)/(3x+6)=7/5 → 25x+30=21x+42 → x=3. A=15.

Question 4

If 8 workers can complete a task in 15 days, how many days will 12 workers take to complete the same task?

Accepted Answer

10 days

Answer

Total work = 8×15 = 120 worker-days. With 12 workers: 120/12 = 10 days.

Question 5

The simple interest on a sum for 3 years at 8% per annum is Rs 1440. What is the principal?

Accepted Answer

Rs 6000

Answer

SI = PRT/100 → 1440 = P×8×3/100 → P = 144000/24 = 6000.

(AMCAT) Aspiring Minds Computer Adaptive Test Practice Test

(AMCAT) Aspiring Minds Computer Adaptive Test Practice Test

AMCAT Quantitative Ability: Applied Mathematics 2