Logical Reasoning and Analytical Ability for Engineers — Practice

Question 1

Find the next term: 3, 7, 15, 31, 63.

Accepted Answer

The differences 4, 8, 16, 32 double, so the next difference is 64 and the term is 127.

Question 2

A quantity rises by 20 percent and then falls by 20 percent. What is the net change?

Accepted Answer

1.2 x 0.8 = 0.96, a net fall of 4 percent.

Question 3

A pipe fills a tank in 10 hours and another empties it in 15 hours. Both are opened. How long to fill?

Accepted Answer

Net rate 1/10 - 1/15 = 1/30 per hour, so 30 hours.

Question 4

All pumps are machines. Some machines are noisy. Does it follow that some pumps are noisy?

Accepted Answer

No. The pump circle can sit inside the machine circle outside the noisy part, so the conclusion is only possible, not certain.

Question 5

A car goes from A to B at 40 km/h and returns at 60 km/h. What is the average speed?

Accepted Answer

2(40)(60)/(40+60) = 48 km/h.

Question 6

A man walks 5 km north, then 12 km east, then returns to the start in a straight line. What total distance does he cover?

Accepted Answer

The return leg is the hypotenuse, 13 km. The total is 5 + 12 + 13 = 30 km.

Question 7

Pointing to a man, a woman says, 'He is the son of my mother's only son.' How is the man related to her?

Accepted Answer

Her mother's only son is her brother, so the man is her brother's son: her nephew.

Question 8

Rice at 40 per kg is mixed with rice at 60 per kg in equal quantities. What is the mixture cost per kg?

Accepted Answer

The mean of equal parts is 50 per kg.

Practice — Logical Reasoning and Analytical Ability for Engineers