A train covers a distance of 10 km in 12 minutes. If its speed is decreased by 5 km/hr, the time taken by it to cover the same distance is equal to :

A train covers a distance of 10 km in 12 minutes. If its speed is decreased by 5 km/hr, the time taken by it to cover the same distance is equal to :
[A]20\ minutes
[B]15\ minutes
[C]\frac{40}{3}\ minutes
[D]40\ minutes

\mathbf{\frac{40}{3}\ minutes}
Time = 12 minutes = \frac{12}{60}\ hours = \frac{1}{5}\ hours
Speed of train =
= \frac{10}{\frac{1}{5}} = 50\ km/hr
New speed = 50 – 5 = 45 km/hr
\therefore Required\ Time = \frac{Distance}{Speed}
= \frac{10}{45} = \frac{2}{9}\ hour
= \frac{2}{9}\times 60 = = \frac{40}{3}\ minutes
Hence option [C] is correct answer.

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