Question

a boy Run for 20 minutes at a uniform speed of 18 km/h hour at what speed should be Run for the next 40min.so that the average speed comes 24km/h​

Answer 1

Let the average speed be x

time ( minutes) - 20 , 40

speed - 18 km/ hr , x

20/18 =40/x

cross multiple

20 × x = 18 × 40

x = 18 × 40 /20

now , 40 and 20 will cancel and and will be 2 and then cancel 2 and 18

x = 9 ans