SOLUTION: Could you please help me on how to solve this problem; I tried to figure out the answer but it do not look right. "John found his plane could fly at 6 times the speed of the win

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Question 450568: Could you please help me on how to solve this problem; I tried to figure out the answer but it do not look right.
"John found his plane could fly at 6 times the speed of the wind. He flew 700 miles upwind in 3 hours more than it took to fly 560 miles downwind. What was the speed of the plan in still air?"
My answer: (a). (A + W)T_D = D_D
(b). (A � W)T_U = D_U
(6W + W)(T_U + 3) = 560 →
(6W + W)T_U = 700
7WT_U + 3W = 560 →
7WT_U = 700 →
WT_U = 100
7(100) + 3W = 560 →

Answer by rwm(914) (Show Source):
You can put this solution on YOUR website!
John found his plane could fly at 6 times the speed of the wind. He flew 700 miles upwind in 3 hours more than it took to fly 560 miles downwind. What was the speed of the plan in still air?"
upwind=against the wind
let
wind=w
downwind=+w
upwind=-w
p=plane
p=6w
r*t=d
(p-w)(3+t)=700
(p+w)t=560
(6w-w)(3+t)=700
(6w+w)t=560
(5w)(3+t)=700
w*(3+t)=140
(7w)t=560
wt=80
w=80/t
w=140/(3+t)
80/t=140/(3+t)
4/t=7/(3+t)
4*(3+t)=7t
12+4t=7t
12=3t
4=t
wt=80
w=20
p=6*w=120 in still air