Solve the problem.

Question

When a plane flies with the​ wind, it can fly 840 miles in 3 hours. When the plane flies in the opposite​ direction, against the​ wind, it takes 7 hours to fly the same distance. What is the average velocity of the​ wind?

Answer 1

So, let's say I can row 5 mph and the river is running at 6 mph. Going downstream, I'd travel 5 + 6 = 11 mph.

Trying to row upstream, you'd end up going 5 - 6 = -1 mph, so you'd be slowly drifting backward.

d = rt

840 = 3(p + w)

840 = 7(p - w)

280 = p + w

120 = p - w

2p = 400

p = 200

280 = 200 + w

w = 80 mph