Help me with this word problem please!

Question

Flying against the wind, a jet travels 2040 miles in 3 hours. Flying with the wind, the same jet travels 4320 miles in 4 hours. What is the rate of the jet in still air and what is the the rate of the wind?

Answer 1

let j= jet speed in still air, w = wind speed

distance divided by time = speed

2040/3 = j-w = 680 against the wind

4320/4 = j+w = 1080 with the wind

add to eliminate w get

2j = 1760, divide by 2

j = 880 mph for the jet in still air

w= 1080-880 = 200 mph for the wind speed