Position of a moving body?
15. a car travels a certain distance with a speed of 50 km. p.h. and retums with a
speed of 40 km. p.h. calculate the average speed for the whole journey. (hint
suppose that the certain distance travelled by the car with a speed of 50 km/h
is x so that he total distance travelled becomes x + x = 2x)

44.4 kmp.h

Explanation:

Take car is going x distance with . And will come back same distance x There for, time taken to going can be taken as t1

t1 = Distance / Speed

t1 = x / 50 h

time taken to come back can be taken as = t2

t2 = Distance / Speed

t2=  x/ 40 h

Average speed  = Total distance travel by the car /  total time

                           = 2x / ( x/50 + x/40 )

                           = 2 × 50×40 / (90)

                          = 44.4 kmp.h

to treat tumors in the body