Question

Adam left the science museum and traveled toward the mountains. Krystal left two hours later traveling 28 mph faster in an effort to catch up to him. After three hours Krystal finally caught up. Find Adam's average speed.

Answer 1

Answer:

Adam's average speed is 42 mph

Explanation:

Let Adam's average speed be x

Krystal travelled 28 mph faster than Adam

Therefore, Krystal's average speed is (x + 28) mph

Krystal left 2 hours after Adam and caught up with him after 3 hours

Total time taken for Adam to travel a distance d m = 2 hours + 3 hours = 5 hours

Time taken for Krystal to travel the same distance (catch up with him) = 3 hours

Average speed = distance/time

distance = average speed × time

Since both travelled the same distance

5(x) = 3(x+28)

5x = 3x + 84

5x - 3x = 84

2x = 84

x = 84/2 = 42 mph

Adam's average speed is 42 mph