Question

Two trains leave the station at the same time, one heading east and the other west. The eastbound train travels 18 miles per hour slower than the westbound train. If the two trains are 320 miles apart after 2 hours, what is the rate of the eastbound train?

Answer 1

71 mph

Explanation:

Lets call the speed of the eastbound train E and the speed of the westbound train W.

E = W - 18

distance travelled = speed * time

thus

Wt + Et = 320

Wt + (W - 18)t = 320

factor out t

t * (2W - 18) = 320

t = 2 hours

2 * (2W - 18) = 320

2W - 18 = 160

2W = 178

W = 89

Then, E = (89) - 18 = 71 mph