Question

two trains leave the station at the same time, one heading west and the other east. the westbound train travels at 95 miles per hour. the eastbound train travels at 115 miles per hour. how long will it take two trains to be 462 miles apart ?

Answer 1

Remark
They are travelling in opposite directions. Their distances will be added until that distance = 462 miles.

You need only add the r*t values together. You do not need to find the distance.

Givens 
d = 462 miles
r1 = 115 mph
r2 = 95 mph
t = the time each was traveling.

Formula
r1 * t   +  r2*t = d

Substitute and solve
95 * t   +   115 * t = 462   Add the like terms on the left.
210 * t  = 462    Divide by 210
t = 462 / 210
t = 2.2 hours.

t = 2 1/5 hours

t = 2 hours  and 12 minutes 
All three answers are the same.