Question

2. A train travels a distance of 30 km with a uniform speed of 54 km/h.It travels another distance of 50 km with a uniform speed of 90 km/h.Calculate the average speed of the train.

Answer 1

The average speed is defined as:

$v=\frac{d}{t}$

Then for the first 30 km it took:

$t=\frac{30}{54}=0.556$

hours.

The second distance of 50 km took:

$t=\frac{50}{90}=0.556$

Therefore the average speed is:

$v=\frac{30+50}{0.556+0.556}=72$

72 km/h.