Multiple choice

A boy walking at the speed of 15 km/hr reaches his school 18 minutes late. Next time, he walks at the speed of 20 km/hr and reaches his school 10 minutes late. Find the distance between his school and his house?

  1. 8/7 km

  2. 8 km

  3. 6 km

  4. 10 km

  5. 5 km

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

Difference between time = 18 - 10 = 8 min

= 8/60 hr

= 2/15 hr

Required distance = ((Speed1 * Speed2)/(Speed1 - Speed2)) * difference of time

Required distance = ((15 * 20)/(20 - 15)) * (2/15)

                          = (15 * 20 * 2)/(5 * 15) = 8 km

It is the correct answer.