Numerical Reasoning Speed, Distance, and Time 2

Question 1

Two trains, 200 m and 150 m long, travel toward each other at 40 m/s and 60 m/s respectively. How long does it take for them to completely pass each other?

Accepted Answer

3.5 seconds

Answer

Total distance = 350 m; Relative speed = 100 m/s; Time = 350 ÷ 100 = 3.5 seconds.

Question 2

A car travels from city A to city B at 60 mph and returns at 40 mph. What is the average speed for the round trip?

Accepted Answer

48 mph

Answer

Harmonic mean: 2 × 60 × 40 ÷ (60 + 40) = 4800 ÷ 100 = 48 mph.

Question 3

A 300-meter-long train passes a stationary pole in 15 seconds. What is the train's speed in km/h?

Accepted Answer

72 km/h

Answer

Speed = 300 ÷ 15 = 20 m/s = 20 × 3.6 = 72 km/h.

Question 4

Walking at 6 km/h, a man is 10 minutes late. Walking at 9 km/h, he is 5 minutes early. What is the distance to his destination?

Accepted Answer

4.5 km

Answer

Setting up the equation: d/6 − d/9 = 15/60; solving gives d = 4.5 km.

Question 5

A motorboat travels 24 km upstream and 36 km downstream in equal time. If the stream speed is 4 km/h, what is the boat's speed in still water?

Accepted Answer

20 km/h

Answer

24/(b−4) = 36/(b+4) gives 24b+96 = 36b−144; solving gives b = 20 km/h.

Numerical Reasoning Practice Test

Numerical Reasoning Practice Test

Numerical Reasoning Speed, Distance, and Time 2