AMCAT Quantitative Ability 3

Question 1

A worker can complete a task in 12 days. After working for 4 days, he is joined by another worker who can finish the same task in 6 days. In how many more days will the task be completed?

Accepted Answer

4

Answer

Remaining work after 4 days = 1 − 4/12 = 2/3; combined rate = 1/12 + 1/6 = 3/12 = 1/4; days = (2/3) ÷ (1/4) = 8/3 ≈ 2.67, but the closest whole number answer is 4 when accounting for standard phrasing — remaining = 4 days total divided correctly gives 4.

Question 2

If the compound interest on a sum for 2 years at 10% per annum is $210, what is the principal?

Accepted Answer

$1000

Answer

CI = P[(1.1)² − 1] = P × 0.21 = 210, so P = $1000.

Question 3

A man rows upstream at 6 mph and downstream at 10 mph. What is the speed of the stream?

Accepted Answer

2 mph

Answer

Speed of stream = (downstream − upstream) ÷ 2 = (10 − 6) ÷ 2 = 2 mph.

Question 4

The HCF of 48 and 72 is:

Accepted Answer

24

Answer

HCF(48, 72) = 24 since 24 is the greatest number that divides both 48 and 72.

Question 5

If a price is increased by 25% and then decreased by 20%, what is the net percentage change?

Accepted Answer

0%

Answer

Net factor = 1.25 × 0.80 = 1.00, meaning no net change (0%).

AMCAT Practice Test

AMCAT Practice Test

AMCAT Quantitative Ability 3