Remark
The trick here is to realize that between them they will cover 600 miles
Train one
r = 90 mph
t = ?? [same for both trains]
d = d1
Train Two
r = 75 miles / hour
t = ?? [same for both trains]
d = d2
Equation.
basically d = r*t
d_train1 + d_train2 = total_distance
90*t + 75*t = 600
Combine and solve
165t = 600 Divide by 165
t = 600/165
t = 3.64 hours <<<<<< Answer
