A car leaves a city and travels east at 50 mph Two hours lat

A car leaves a city and travels east at 50 mph. Two hours later another car traveling at 90 mph leaves the same city in pursuit of the first car.
How many miles from the city will the second car overtake the first?

Solution

D=RT
D=50*T
D=90(T-2)
SET THE 2 DISTANCES EQUAL & SOLVE FOR T
50T=90(T-2)
50T=90T-180
50T-90T=-180
-40T=-180
T=-180/-40
T=4.5 HOURS AFTER THE FIRST CAR LEAVE THE SECOND CAR WILL OVERTAKE IT.
PROOF:
50*4.5=90(4.5-2)
225=90*2.5
225=225