distance rate and time

Question

the north bound train travels 18 miles per hour faster than the southbound train. After 2 hours they are 220 miles apart. At what speeds are the two trains traveling

Answer 1

in 2 hours the trains traveling in opposite directions are 220 miles apart. That's 110 mph hour divided between the two trans. Their speeds sum to 110 mph. one is 18 mph faster.

F = S + 18

F + S = 110

substitute 1st value of F for S into the 2nd equation

S + 18 + S = 110

2S = 110 -18 = 92

S = 92/2 = 46 mph for the slower train

F = 46+18 = 64 mph for the faster train

in 2 hours they've gone 2(46) + 2(64) = 92 _128 = 220 miles apart