SOLUTION: A man takes twice as long to row against the current as with it. He rows at 6 mph in still water. If the current flows at x mph, write an equation in x and solve it to find x

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Question 756490: A man takes twice as long to row against the current as with it. He rows at 6 mph in still water. If the current flows at x mph, write an equation in x and solve it to find x
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
the rate of the boat in still water is equal to 6 mph.
the rate of the current = x
the man takes twice as long to row against the current as with it.
this means that his rate against the current is 1/2 the rate with the current.
this also mean that his rate with the current is 2 times the rate against the current.

the rate with the current can be represented by 6 + w
the rate against the current can be represented by 6 - w

since the rate with the current is 2 times the rate against the current, we have an equation that states:

6 + w = 2 * (6 - w)

we want to solve for w.

simplify the equation to get:

6 + w = 12 - 2w
add 2w to both sides of the equation and subtract 6 from both sides of the equation to get:

3w = 6

divide both sides of the equation by 2 to get:

w = 2

when w = 2, ....

6 + w = 8
6 - w = 4

6 + w is 2 times 6 - 2 which is correct based on our original assumptions that the rate of the boat with the current is 2 times the rate of the boat against the current.

answer is the rate of the current is equal to 2 mph.