Question

3. A boy walks from his home to a post office at a distance of 0.5m in 20min. He then return to his home in time 25min. Find the average speed of the boy.
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Answer 1

Answer:

Let the distance of school and house is x k m

Then time taken at speed 2.5 km\hr=

2.5

x

hr

And time taken at speed 4 km\hr=

4

x

hr

∴

2.5

x

−

4

x

=

60

12

⇒

10

4x−2.5x

=

5

1

⇒x=3 km

Then the distance of school and house is 3 k m