A train travels a distance of 15 km with a speed of 30 kmph and remaining distance of 15 kilometre with the speed of 45 kmph. Find its average speed in kmph.

Given:  A train travels a distance of 15 km with a speed of 30 km h and remaining distance of 15 kilometre with the speed of 45 kilometre per hour .

Solution:

Time taken to travel 15 km with a speed of 30 kmph:

$= \frac{Distance}{speed} =  \frac{15}{30} =  \frac{1}{2}  hour$

Time taken to travel 15 km with a speed of 45 kmph

$= \frac{Distance}{speed} =  \frac{15}{45} =  \frac{1}{3}  hour$

Total distance travelled = 15 + 15 = 30 km

Total time taken = $\frac{1}{2}  +   \frac{1}{3}  =  \frac{5}{6}  hour$

Average speed = $\frac{Total \ Distance}{Total \ time}$

                           = $\frac{30}{ 5/6}$

                           = $30 \times 6/5$ = 36 kmph

So, Average speed = 36 kmph

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Updated on: 10-Oct-2022

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