What was the speed of plane in still air

Question

against the wind a commercial airline in south america flew 952 miles in 4 hours. with tailwind the return trip took 3.5 hours. What was the speed of the plan in still air

Answer 1

against the wind a commercial airline in south america flew 952 miles in 4 hours. with tailwind the return trip took 3.5 hours. What was the speed of the plan in still air

Speed multiplied by time gives distance.

Against the wind:
4(s-w) = 952
(s-w) = 952/4 = 238 mph

With the wind:
3.5(s+w) = 952
(s+w) = 952/3.5 = 272 mph

We can eliminate the wind component by adding the two equations.

s -  w = 238
s + w = 272
-----------------
2s      = 510

2s = 510 mph
s = 510 mph / 2
s = 255 mph