SOLUTION: Julie and Eric row their boat (at a constant speed) 63 miles downstream for 7 hours, helped by the current. Rowing at the same rate, the trip back against the current takes 9 hours

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Julie and Eric row their boat (at a constant speed) 63 miles downstream for 7 hours, helped by the current. Rowing at the same rate, the trip back against the current takes 9 hours      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 880553: Julie and Eric row their boat (at a constant speed) 63 miles downstream for 7 hours, helped by the current. Rowing at the same rate, the trip back against the current takes 9 hours. Find the rate of current
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Julie and Eric row their boat (at a constant speed) 63 miles downstream for 7 hours, helped by the current. Rowing at the same rate, the trip back against the current takes 9 hours. Find the rate of current
***
let x=constant speed of boat
let c=speed of current
x+c=speed of boat traveling with the current
x-c=speed of boat traveling against the current
travel time=distance/speed
..
63%2F%28x%2Bc%29=7
63%2F%28x-c%29=9
..
7x+7c=63
9x-9c=63
..
63x+63c=567 (mult. by 9)
63x-63c=441 (mult. by 7)
subtract:
126c=126
c=1
rate of current=1 mph