math
posted by Anonymous .
A certain aircraft can fly 768 miles with the wind in 4 hours and travel the same distance against the wind in 6 hours. what is the speed of the wind?

speed of the plane without wind  x mph
speed of the wind  y mph
time with wind :
4(x+y) = 768
x + y = 192
time against wind:
6(xy) = 768
xy = 128
add them
2x = 320
x = 160
then 160+y = 192
= 32
windspeed = 32 mph
check: speed with wind = 160+32 = 192 mph
time to go 768 = 768/192 = 4
speed against wind = 16032 = 128
time against wind = 768/128 = 6