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A plane flew 1225 mi in 5 hr with the wind. It would take 7 hr to travel the same distance against the wind. What is the speed of the plane in still air and the speed of the wind?

Respuesta :

Answer:

wind speed 35 miles per hour

plane speed 210 miles per hour

Explanation:

Let us call p the place speed and w the wind speed.

We know that

p + w = 1225/5 = 245

p - w = 1225/7 = 175

adding the two equations above gives

2p = 245 + 175

2p = 420

dividing both sides by 2 gives

p = 210 miles per hour.

putting in the value of p in p + w = 245 gives

210 + w = 245

w = 245 - 210

w = 35 miles per hour