Question

A car moves a distance of 200 m. It covers the
first half of the distance at speed 40 km/h and
the second half of the distance at speed v. If the
average speed of the car is 48 km/h then find
the value of v ?​

Answer 1

Answer:

Answer is v=60 km/h

48= 200/((100/40)+(100/v) )

or 1/40+1/v= 2/48=1/24

or 1/v=1/24-1/40=2/120=1/60

or v=60km/h

[Alt: v_av = (2v_1 v_2)/(v_1+v_2 ) => 48= (2×40×v)/(40+v) => v=60 km/h]