Question 62

A man walks at a speed of 3 kmph. He doubles his speed after reaching exactly half way. He walks for 5 hours in all. What is the total distance travelled by him?

Solution

Let the time taken to cover first half of the distance be x hrs and speed = 3 kmph

Time taken to cover the remaining distance is 5-x hrs and speed = 6 kmph

Distance will be same in both case,

So,

3x = 6(5-x)

3x = 30 - 6x

9x = 30

x = $$\frac{30}{9}=\frac{10}{3}$$ hours

Half distance =Speed $$\times\ Time=\frac{10}{3}\times3=10\ $$ km

Total distance = $$2\times10=20\ $$ km.

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