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

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 will be :
[A]10 minutes
[B]11 minutes 20 sec
[C]13 minutes
[D]13 minutes 20sec

13 minutes 20sec
Speed of train = \frac{Distance}{Time}
=\frac{10}{\frac{12}{60}}km/h
=\frac{10\times 60}{12} = 50km/h
New Speed = 45km/h
∴ Required Time = \frac{10}{45}hour
= \frac{2}{9}\times 60 minutes
= \frac{40}{3} minutes
= 13 minutes 20 seconds
Hence option [D] is correct answer.

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