Question 874266
a car traveling 80 kilometers per hour
time = 30/3600 hours = 1/120 hours
 After 30 seconds,
d= 80*1/120


 is passed by a second car going in the same direction at a constant speed.
let speed be x
  After 30 seconds,
d= 1/120 * x

 the two cars are half a kilometer apart.

1/120*x - 80/120 = 1/2

(x-80)/120 =1/2

x-80=60
x=80+60
x=140 km/h.........speed of second car


 Find the speed of the second car .