Respuesta :
s=plane's speed
w=windspeed
travels490 mh with wind
450 agains wind
s+w=490mph
s-w=450
add them toegether
s+w=490
s-w=450 +
2s+0w=940
2s=940
divide by 2
s=470
find wind speed
s+w=490
470+w=490
w=20
windspeed=20mph
planespeed=470mph
w=windspeed
travels490 mh with wind
450 agains wind
s+w=490mph
s-w=450
add them toegether
s+w=490
s-w=450 +
2s+0w=940
2s=940
divide by 2
s=470
find wind speed
s+w=490
470+w=490
w=20
windspeed=20mph
planespeed=470mph