How do I set up this problem to be solved?

Question

A plane flies 495 miles with the wind and 440 miles against the wind in the same length of time. If the speed of the wind is 10 mph, find the speed of the plane in still air.

Answer 1

d = r · t

d / r = t

495 / (r + 10) = 440 / r    the times are equal

 

Can you solve for t then answer the question?