To travel 672 km, an Express train takes 14 hours more than Rajdhani. If however, the speed of the Express train is doubled, it takes 8 hou… — Answer & Discussion

To travel 672 km, an Express train takes 14 hours more than Rajdhani. If however, the speed of the Express train is doubled, it takes 8 hours less than Rajdhani. The speed of Rajdhani is

A30.5 km/hr
B14.3 km/hr
C38.7 km/hr
D22.4 km/hr

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Discussion 1

CCommunity02 Jul 2019

Let time taken by Rajdhani be y hours

Let the speed of Express train be x km/hr

Time taken by Express train = 672/x

672/x = y + 14 - - - - - (1)

New speed of Express train be 2x km/hr

Time taken by Express train = 672/2x

672/2x = y – 8 - - - - - - (2)

From (1) and (2) we get x = 15.27 km/hr and y = 30 hr

Speed of Rajdhani = 672/30 = 22.4 km/hr