Posted by alms on Tuesday, April 23, 2013 at 7:57pm.
Paul Websters motorboat can travel 15 mph in still water. Traveling with the current of a river, the boat can travel 20 miles in the same time it takes to go 10 miles againt the current. Find the speed of the current.

math algebra  Henry, Friday, April 26, 2013 at 8:39pm
(15+Vc)t = 20
Eq1: 15t + Vc*t = 20
(15Vc)t = 10
Eq2: 15t  Vct = 10
Add Eq1 and Eq2:
15t + Vct = 20
15t _ Vct = 10
30t = 30
t = 1 h.
15*1 + Vc*1 = 20
Vc = 2015 = 5 mi/h. = Velocity of current.