SOLUTION: A boat can travel 45 mph in still water. If it travels 265 miles with the current in the same length of time it travels 185 miles against the current what is the speed of the curre

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: A boat can travel 45 mph in still water. If it travels 265 miles with the current in the same length of time it travels 185 miles against the current what is the speed of the curre      Log On


   

Question 956277: A boat can travel 45 mph in still water. If it travels 265 miles with the current in the same length of time it travels 185 miles against the current what is the speed of the current? Im not sure how to set this equation, help please.
Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
c=rate of current
265 miles/45mph+r=185 miles/45mph-r Cross multiply.
(265 miles)(45mph-r)=(185 miles)(45mph+r)
%2811925mi%5E2%2Fhr%29-%28265rmi%29=%288325mi%5E2%2Fhr%29%2B185rmi Add 265r mi to each side.
11925Mi%5E2%2Fhr%29=%288325mi%5E2%2Fhr%29%2B%28450rmi%29Subtract 8325mi^2/hr from each side.
3600mi%5E2%2Fhr=450rmi Divide each side by 450 mi
8mph=rANSWER The rate of the current was 8mph
CHECK:
265 miles/45mph+r=185 miles/45mph-r
265 miles/45mph+8mph=185 miles/45mph-8mph
265 miles/53mph=185 miles/37 mph
5 hours=5 hours