Calculus Question!!!!! Need HELP!!!?

Question

A person 2 meters tall walks directly away from a streetlight that is 8 meters above the ground. If the person is walking at a constant rate and the person's shadow is lengthening at the rate of 4/9 meter per second, at what rate, in meters per second, is the person walking?

Answer 1

if x is the distance to the streetlight and s the length of the shadow
(x+s)/8= s/2 so 2x+2s= 8s
and x=3s
so dx/dt=3ds/dt =3*4/9 =4/3 m/s(velocity)