Flying against the wind, an airplane travels 5600 km in 8 hours. Flying with the wind, the same plane travels 9900 km in 9 hours.

1 answer

speed of plane without wind ---- x km/h
speed of wind --------- y km/n

5600/(x-y) = 8
700/(x-y) = 1
x-y = 700 **

9900/(x+y) = 9
1100/(x-y) = 1
x + y = 1100 ***

add ** and *** to find x
then sub back into **