Julie and eric row their boat (at a constant speed) 18 miles downstream for 3 hours by the current. rowing at the same rate, the trip back against the current takes 6 hours. find the rate of the boat in still water.

Answer

Find out the the rate of the boat in still water.

To proof

let us assume that the speed of the boat in the still water = u

let us assume that the speed of the current = v

Formula

As given

18 miles downstream for 3 hours

Now for the downstream

u + v = 6

now for the upstream

As given

the trip back against the current takes 6 hours

u-v = 3

Than the two equation becomes

u + v = 6 and u - v = 3

add both the above equation

we get

2u = 9

u = 4.5miles per hour

put this in the  u - v = 3

4.5 -v = 3

v =1.5 miles per hour

The rate of  the boat in the still water is  4.5miles per hour .

Hence proved

step-by-step explanation:

options