Question

In a car race of 20 km distance, a car covers initial distance of 10 km at the speed of 50 km/hr. At what speed the

car must travel the remaining distance so that its average speed at the end of the race is 60 km/hr.
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Answer 1

Explanation:

let the next ten km speed be x

average speed=(2v1v2)/v1+v2

60 =2×50×x/50+x

60(50+x)=100x

3000+60x=100x

3000=40x

x=75km/h