How long did the freight train travel before the passenger train caught up?

Question

A freight train left Abuja and traveled toward the repair yard at an average speed of 34 km/h. A passenger train left 3 hours later and traveled in the same direction but with an average speed of 85 km/h. How long did the freight train travel before the passenger train caught up?

Answer 1

distance=rate*time

d=r*t

d=34*t (freight)

d=85*(t-3) (passenger)

equate the two right sides

34t=85(t-3)

34t=85t-255

34t-85t=-255

-51t=-255

51t=255

t=255/51

t=5 hours before the passenger train caught up to the freight train