Two trains going in opposite directions leave at the same ti

Two trains going in opposite directions leave at the same time. Train B travels 5 mph faster than train A. In 6 hours the trains arc 690 miles apart. Find the speed of each. The speed of train A is mph.

Solution

let the speed of train A is \'x\'

then the speed of trainB is x+5

the combined speed = x + x+5 = 2x+5

given distance(d) = 690 miles

time(t) = 6 hours

so speed = distance / time

2x +5 = 690/6

6(2x+5) =690

12x +30 =690

12x =690 -30

12x =660

x =55 mph ( trainA speed)

train B speed is = x+5 = 55 +5 =60 mph