SOLUTION: sasha can row her boat 5 miles per hour on still water. She could travel 48 miles downstream in twice the tim eit takes to travel 6 miles upstream. What is the speed of the water

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: sasha can row her boat 5 miles per hour on still water. She could travel 48 miles downstream in twice the tim eit takes to travel 6 miles upstream. What is the speed of the water      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 978972: sasha can row her boat 5 miles per hour on still water. She could travel 48 miles downstream in twice the tim eit takes to travel 6 miles upstream. What is the speed of the water
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +c+ = the speed of the current
+5+ mi/hr = the speed of the boat in still water
Let +t+ = time in hrs to travel upstream
--------------------
Going downstream:
(1) +48+=+%28+5+%2B+c+%29%2A2t+
Going upstream:
(2) +6+=+%28+5+-+c+%29%2At+
----------------------
(1) +48+=+10t+%2B+2c%2At+
(2) +6+=+5t+-+c%2At+
----------------------
(2) +c%2At+=+5t+-+6+
By substitution:
(1) +48+=+10t+%2B+2%2A%28+5t+-+6+%29+
(1) +48+=+10t+%2B+10t+-+12+
(1) +20t+=+60+
(1) +t+=+3+
---------------
(2) +6+=+%28+5+-+c+%29%2A3+
(2) +6+=+15+-+3c+
(2) +3c+=+9+
(2) +c+=+3+
The speed of the current is 3 mi/hr
check:
(1) +48+=+%28+5+%2B+c+%29%2A2t+
(1) +48+=+%28+5+%2B+3+%29%2A2%2A3+
(1) +48+=+8%2A2%2A3+
(1) +48+=+48+
OK