Question

a boy run for 20 min. at a uniform speed of 18km/h. at what speed should he run for the next 40 min. so that the averge speed comes 24 km/hr.

Answer 1

Av. Speed =total distance / total time taken...
24 = 18 + x \ 20/60+ 40/60
As the av. Speed in km/hr.. So we have to change min. Into hour..
By solving ans. Will be... 6