Question

A car covers one-fourth of the distance between two places with an average speed v1. If it travels with an average speed v2 for the remaining part of its journey, then find the average speed for the entire journey.

Answer 1

Answer:

Let the distance to be covered = 5 units.

Fraction of the journey covered at v speed= 2/5.

Distance covered at v speed = 2 units

Time taken to cover 2 units at v = 2/v units of time

Fraction of journey covered at v' speed= 3/5

Distance covered at v’speed= 3 units.

Time taken to cover 3 units at v'= 3/v’ units of time.

Total time taken to cover 5 units of journey= (2/v)+(3/v')= (2v’ + 3 v)/vv'

Average speed = total distance covered ÷ total time taken = 5 ÷ ( 2v’ + 3 v)/vv'= 5 v v'/ (2v’ + 3v)

Explanation:

use this formula