Question

A jet plane traveling at 550 mph overtakes a propeller plane traveling at 200 mph that had a 4 hour head start. How far from the starting point are the planes?

Answer 1

The plane traveling 200 mph, started 4 hours earlier.

As at when they meet, let the 550 mph, have traveled for x hours.

The 200 mph would have traveled (x + 4) hours, since it started 4 hours earlier.

As at when they met, the distance covered is the same:

Distance = Speed * hour

550x = 200(x + 4)

550x = 200x + 200*4

550x = 200x + 800

550x - 200x = 800

350x = 800

x = 800/350

x = 16/7 hours.

The distance travelled = 550x = 550 * 16/7 = 8800/7 miles

The distance = 8800 / 7 miles  or ≈ 1257.14 miles

Hope this explains it.