Question

A car covers the first half of the distance between two place at a speed 40 kilometre per hour and second half of 60 km per hour what is the average speed of car​

Answer 1

Answer:

Average speed of the car is 48 km/hr

Explanation:

let total distance car covered is x

let x/2 distance cover in time t1 with speed of 40 km/hr

and  x/2 distance cover in time t2 with speed of 60 km/hr

$t_{1} =Distance/speed =\frac{0.5x}{40} \\t_{2} = \frac{0.5x}{60}$

Total time of travel is

$t_{1}+t_{2}=\frac{0.5x}{40} +\frac{0.5x}{60}\\t_{1}+t_{2}=\frac{1.5x+x}{120} \\t_{1}+t_{2}=\frac{2.5x}{120} \\t_{1}+t_{2}=\frac{x}{48}$

Average speed is = $total distance /total time$

=x/(x/48)

=48 km /hr