V1 = X mi/h
d1 = X * 3 = 3x miles head start.
V2 = (X+15)mi/h
(X+15)*T = X*T + 3x
(X+15)*6 = 6x + 3x
6x + 90 = 9x
3x = 90
X = 30 mi/h
X+15 = 30+15 = 45 mi/h.
a carload of fraternity brothers leave their house for a long weekend trip. three hours later a second carload of brothers leaves the same house and travels the same path. if the second care drives and average of 15 mph faster than the first, what is the average speed of eavh car if it takes the second car six hours to catch up to the first
1 answer
1 answer