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 :

13 minutes 20sec
Speed of train $latex = \frac{Distance}{Time}&s=1$
$latex =\frac{10}{\frac{12}{60}}km/h&s=1$
$latex =\frac{10\times 60}{12} = 50km/h&s=1$
New Speed $latex = 45km/h&s=1$
∴ Required Time $latex = \frac{10}{45}hour&s=1$
$latex = \frac{2}{9}\times 60 minutes&s=1$
$latex = \frac{40}{3} minutes&s=1$
$latex = 13 minutes 20 seconds$
Hence option [D] is correct answer.