A plane traveled 4030 miles with the wind in 6.5 hours and 3120 miles against the wind in the same amount of time.

Question

Find the speed of the plane in still air and the speed of the wind.

Answer 1

Use the D=RT chart technique.

Let windspeed be w, plane's speed (w/o wind) be p mi/hr.

4030 = 6.5(p+w)

3120 = 6.5(p-w)

 

Next, observe that each equation could be manipulated to isolate the quantity in parentheses, by dividing 6.5 into ech side.

That will give you p+w on the right side of first equation & p-w on right side of 2nd equation.

By adding, you will get 2p = some particular number.

You will have unlocked the key to solving this entire system, solving for p first and then for w.