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**unique****Member**- Registered: 2006-10-04
- Posts: 419

A fighter plane could fly at 4 times the speed of the wind. as a result, it could travel 60 miles downwind in 1 hour longer than it took to travel 300 miles upwind. what waas the fighter plane's speed in still air?

Desi

Raat Key Rani !

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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,588

I think you have upwind and downwind mixed up, or else I have their definitions messed up.

Downwind is with the wind I thought, and upwind is against the wind.

**igloo** **myrtilles** **fourmis**

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**unique****Member**- Registered: 2006-10-04
- Posts: 419

OH MY GOD i messed it up.....

i had to write.... 600 instead of 60

A fighter plane could fly at 4 times the speed of the wind. as a result, it could travel 600 miles downwind in 1 hour longer than it took to travel 300 miles upwind. what waas the fighter plane's speed in still air?

But the upwind and downwind thing is right.

Desi

Raat Key Rani !

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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,588

Let's see, uh, 5 times wind speed times (uptime + 1) = 2 (3 times wind speed times uptime).

600 = 5w(u+1) = 6wu

600 = 5wu + 5w = 6wu

Make into 2 equations and subtract 5/6ths of equation from the other and

solve for w, the wind speed.

100 = 5w

wind speed = 20mph

plane speed = 80 in still air.

Didn't check answer. You can. (as Krassi would say)

**igloo** **myrtilles** **fourmis**

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