Question 118

A car travels 20% slower than a train. Both starts from point A at the same time and reach point B 240 km away at the same time. On the way the train takes 48 minutes for stopping at the stations. What is the speed (in km/hr) of the car?

Solution

Let speed of train = $$10x$$ km/hr

=> Speed of car (20% slower) = $$10x\times\frac{80}{100}=8x$$ km/hr

Both take same time to travel 240 km, hence

=> $$\frac{240}{8x}=\frac{240}{10x}+\frac{48}{60}$$

=> $$240\times(\frac{1}{8x}-\frac{1}{10x})=\frac{4}{5}$$

=> $$\frac{5-4}{40x}=\frac{1}{300}$$

=> $$40x=300$$

=> $$x=\frac{300}{40}=7.5$$

$$\therefore$$ Speed of car = $$8\times7.5=60$$ km/hr

=> Ans - (D)

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