Walter and John leave in their cars at the same time. Walter drives 252 miles. John drives 10 miles per hour faster than Walter and travels 312 miles. If Walter and John arrive at their destinations at the same time, determine how fast Walter is driving?

42 miles per hour

Explanation:

Let d = distance moved by Walter = 252 miles and D = distance moved by John = 312 miles. Let v be the speed of Walter and V be the speed of John. From the question, V = v + 10. Since they both arrive at the same time, and time = distance/speed

d/v = D/V

d/v = D / (v + 10)

v/d = (v + 10) / D

Substituting the values of d and D, we have

v/252 = (v + 10) / 312

v + 10 = 312v/252

v + 10 = 1.238v

collecting like terms, we have

1.238v - v = 10

0.238v = 10

v = 10/0.238 = 42 miles per hour

So Walter is driving at a speed of 42 miles per hour