SOLUTION: When Monique rented a boat to a cruise on the Sandy River, she was told that the boat takes 1.5 times as long to go 360 miles up a river than to return. If the boat cruises at 15

Algebra ->  Rate-of-work-word-problems -> SOLUTION: When Monique rented a boat to a cruise on the Sandy River, she was told that the boat takes 1.5 times as long to go 360 miles up a river than to return. If the boat cruises at 15       Log On


   

Question 88006: When Monique rented a boat to a cruise on the Sandy River, she was told that the boat takes 1.5 times as long to go 360 miles up a river than to return. If the boat cruises at 15 miles per hour in still water, what is the rate of the current?
Answer by uma(370) About Me  (Show Source):
You can put this solution on YOUR website!
Let the rate of current be x mph
Speed of the boat = 15 mph
Distance covered = 360 miles
Speed while going up the river = 15 - x mph
Speed while going down the river = 15 + x mph
Time taken for upward journey = 360/(15 - x)
Time taken for downward journey = 360/(15 + x)
Thus the equation is 360/(15-x) = (1.5) [360/(15+x)]
==> 1/(15-x) = 1.5/(15+x) [dividing by 360 on both sides]
==> 15+x = 1.5(15-x)
==> 15+x = 22.5 - 1.5x
==> x + 1.5x = 22.5 - 15
==> 2.5x = 7.5
==> x = 7.5/2.5
==> x = 3

Thus the rate of the current = 3 mph
Good Luck!!!