Question 910337
r*t=d
with the wind
(r+7)*3=d
3*r+21=d
against the wind
(r-7)*3.2=d
3.2*r-7*3.2=d
3.2*r-22.4=d

3.2*r-22.4=3*r+21
0.2r=43.4/0.2
r=217.0 mph rate plane
distance=224.0*3=672.0
distance=210.0*3.2=672.0
check
(217.0+7)*3= (217.0-7)*3.2
224.0*3=210.0*3.2
672.0=672.0
ok