Question

Ravi starts for his school at 8:20 a.m. on his bicycle. If he travels at a speed of 10Km/ h, then he reaches
his school late by 8 minutes. But on traveling at 16 Km/h he reaches the school 10 minutes early. At
what time does the school start?

Answer 1

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.


Hope this helps!

Answer 2

Answer:

School time will be 9:00 A.M

Please refer the image...