Question

A train travels some distance with a speed of 30km/hr and returns with a speed of 45km/hr. Calculate the average speed of the train.​

Answer 1

Step-by-step explanation:

if a object cover D distance with a speed of u and again cover D distance with a speed of v then

Average speed is equal to (2•u•v)/(u+v)

now

u=30. v=45

A.v speed = (2•u•v)/(u+v)

= (2•30•45)/(30+45)

= 60×45/75

= 4×45/5

=4×9= 36

hence average speed is 36 km/hr

#666

Answer 2

Answer:

37.5 km/hr (EXACT) or 36km/hr (WHOLE)

Step-by-step explanation:

So, the train travels at a speed of 30km/hr.

The train returns at a speed of 45km/hr.

Average (also known as the mean) = 30 + 45/2 = 37.5 km/hr

If you want to make it a whole number, then remember this:

Distance = Speed/time

Time = x

30/x + 45/x/2 - 1.5 = 36 km/hr