Question

A car moves at a speed of 40 miles per hour for half an hour and then at 60 miles per hour for two hours. What is the average speed, measured in miles per hour, for the entire trip?

Answer 1

Answer:

The average speed for the entire trip is 56 miles/hour.

Explanation:

It is given that,

Initially, the car moves with a speed of, v₁ = 40 miles/hour

Initial time, t₁ = 0.5 hours

Distance covered during time t₁,

$d_1=v_1t_1$

$d_1=40\times 0.5$

$d_1=20\ miles$

Then it travels with a speed of, v₂ = 60 miles/hour

Then time taken, t₂ = 2 hours

Distance covered during time t₂,

$d_2=v_2t_2$

$d_2=60\times 2$

$d_2=120\ miles$

The average speed of the car can be calculated as :

$v=\dfrac{d_1+d_2}{t_1+t_2}$

$v=\dfrac{120+20}{0.5+2}$

v = 56 miles/hour

So, the average speed of the car for the entire trip is 56 miles/hour. Hence, this is the required solution.