SOLUTION: A boat. Goes 350 miles down stream in the same time it can go 300 miles upstream. The speed of the current is 7 miles per hour. Find the speed of the boat in still water?

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Question 693460: A boat. Goes 350 miles down stream in the same time it can go 300 miles upstream. The speed of the current is 7 miles per hour. Find the speed of the boat in still water?
Answer by pmatei(79) About Me  (Show Source):
You can put this solution on YOUR website!
To find time you need to divide the distance by the relative speed.
Going upstream the relative speed is the speed of the boat minus the speed of the current. Going downstream the relative speed is the sum of the speed of the boat and the speed of the current.
t=d%5Bup%5D%2F%28v%5Bboat%5D-v%5Bcurrent%5D%29
t=d%5Bdown%5D%2F%28v%5Bboat%5D%2Bv%5Bcurrent%5D%29
Put them together:

Replace with your numbers:
300%2F%28v%5Bboat%5D-7%29=350%2F%28v%5Bboat%5D%2B7%29
350%28v%5Bboat%5D-7%29=300%28v%5Bboat%5D%2B7%29
350v%5Bboat%5D-2450=300v%5Bboat%5D%2B2100
50v%5Bboat%5D=4550
v%5Bboat%5D=91mph