DAA Distance, Speed, and Time Problems 2

Question 1

Two cars start from the same point and travel in opposite directions. Car A travels at 60 km/h and Car B at 80 km/h. How far apart are they after 3 hours?

Accepted Answer

420 km

Answer

Combined speed = 60 + 80 = 140 km/h; distance = 140 × 3 = 420 km.

Question 2

A train 200 m long passes a stationary pole in 10 seconds. What is the speed of the train in km/h?

Accepted Answer

72 km/h

Answer

Speed = 200 ÷ 10 = 20 m/s; converting: 20 × 3.6 = 72 km/h.

Question 3

A car travels from City A to City B at 60 km/h and returns at 40 km/h. What is the average speed for the entire round trip?

Accepted Answer

48 km/h

Answer

Average speed = 2 × 60 × 40 ÷ (60 + 40) = 4800 ÷ 100 = 48 km/h.

Question 4

A cyclist leaves town at 8:00 AM at 12 km/h. A car leaves the same town at 9:00 AM in the same direction at 48 km/h. At what time does the car overtake the cyclist?

Accepted Answer

9:20 AM

Answer

At 9:00 AM the cyclist has a 12 km lead; closing speed = 36 km/h; 12 ÷ 36 = 1/3 hr = 20 min, so 9:20 AM.

Question 5

A train 150 m long travelling at 72 km/h passes another train 100 m long travelling at 36 km/h in the same direction. How long does it take to fully pass?

Accepted Answer

25 seconds

Answer

Relative speed = 72 − 36 = 36 km/h = 10 m/s; total length = 250 m; time = 250 ÷ 10 = 25 seconds.

DAA - Defence Aptitude Assessment Practice Test

DAA - Defence Aptitude Assessment Practice Test

DAA Distance, Speed, and Time Problems 2