Question 69

A starts 3 min after B for a place 4.5 km distant B, on reaching his destination, immediately returns and after walking a km meets A.if A can walk 1 km in 18 minutes, then whatis B's speed ?

Solution

Let B's speed be $$x$$ km/hr and A's speed = $$\frac{60}{18}=\frac{10}{3}$$ km/hr

Distance covered by B in 3 minutes = $$\frac{x}{20}$$ km

Now, time taken by A to travel 3.5 km = Time taken by B to travel 5.5 km - 3 minutes

=> $$3.5\times\frac{3}{10}=\frac{5.5}{x}-\frac{3}{60}$$

=> $$1.05+0.05=\frac{5.5}{x}$$

=> $$x=\frac{5.5}{1.1}=5$$ km/hr

=> Ans - (A)

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