Question

A car travels for three hours. It travels 63 km in first hour, 45 km in second hour and some distance in last hour. If the average speed for the whole journey is 46 km/hr, find the distance traveled in third hour.

1. 20 km
2. 45 km
3. 30 km
4. 10 km
5. 50 km

Answer 1

Correct Answer - Option 3 : 30 km

Given:        

Average speed = 46 km/hr

Total time = 3 hours

Formula Used:

Average speed = Total distance traveled/Total time

Calculations:

Let the distance traveled in third hour be x km.

Total distance = 63 km + 45 km + x km

⇒ 108 + x km

Total time = 3 hr

Average speed = (108 + x)/3 = 46

⇒ 108 + x = 138

⇒ x  = 138 – 108

⇒ x = 30 km

Hence the distance traveled in third hour is 30 km.