math question on black board

Question

A northbound train and a southbound train meet each other on parallel tracks heading in opposite directions. The northbound train travels 8 miles per hour faster than the southbound train. After 2.5 hours, they are 330 miles apart. At what speeds are the two trains traveling?

Write an equation using the information as it is given above that can be used to solve this problem. Use the variable r to represent the speed of the southbound train.

Answer 1

2.5(N+S) = 330

N= S+8= r+8

2.5(r+8+r) =330

2r +8 = 330/2.5 = 132

2r = 132-8= 124

r = 124/2 = 62 mph for Southbound train

N= 62+8 = 70 mph for Northbound train

in 2 1/2 hours Southbound went 2.5(62) =155

in 2 1/2 hours Northbound went 2.5(70)= 175

155+175 = 330 miles apart