Two cars start at an interstate interchanger and travel in t

Two cars start at an interstate interchanger and travel in the same direction at average speeds of 40 miles per hour and 55 miles per hour. How much time must elapse before the two cars are 5 miles apart?

Solution

D=RT
55*T-40T=5
15T=5
T=5/15
T=1/3 OR 20 MINUTES THE 55 MPH. CAR WILL BE 5 MILES AHEAD OF THE 40 MPH. CAR.