Question

Train a has a speed 15 miles per hour greater than that of train

Answer 1

Train a speed = x+15

Train b speed =x

255/x = 300/(x+15)

255(x+15) = 300x

255x +3825 =300x

3825 = 45x

X = 3825/45 =85

Train B  = 85 miles per hour

 Train A = 85+15 = 100 miles per hour