Multiple choice

A bus travels 2/5 of a total journey at its usual speed. The remaining distance is covered by the bus at 6/7 of its usual speed. Due to slow speed, it reaches its destination 50 minutes late. If the total distance is 200 km, then what is the usual speed (in km/hr) of bus?

  1. 20.57

  2. 24

  3. 28

  4. 26.52

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let usual speed be v. Time for 2/5 distance (80km) is 80/v. Time for 3/5 distance (120km) at 6/7v is 120/(6/7v) = 140/v. Total time = 220/v. Usual time = 200/v. Difference = 20/v = 50/60 hours. 20/v = 5/6, so v = 24 km/hr.