Ravi starts for his school at 8:20a.m on his bicycle. If he travels at a speed of 10km/h,
then he reaches his school late by 8minutes, but on travelling at 16km/h, he reaches
the school 10 minutes early. At what time does the school start?
Answers
Answer:
Given that Ravi starts for his school at 8.20 am.
Let the distance be x km.
Let the time taken by Ravi to reach the school be y.
(1) Given that he travels at a speed of 10km/hr and reaches by 8 minutes late.
x/10 = y + 8/60
x/10 = y + 2/15 --- (1)
(2) Given that he travels at a speed of 16km/hr and reaches by 10 minutes early.
x/16 = y - 10/60
x/16 = y - 1/6. ----- (2).
on solving (1) and (2), we get
x/10 - x/16 = 2/15 + 1/6
3x/80 = 9/30
x = 9 * 80/3 * 30
= 8 km. ----- (3)
Substitute (3) in (2), we get
8/16 = y - 1/6
y - 1/6 = 8/16
y - 1/6 = 1/2
y = 1/6 + 1/2
= 2/3 hours
= 2/3 * 60
y = 40 minutes.
Ravi starts school at 8.20am + 40 minutes = 9.00AM.
His school starts at 9.00AM.