SOLUTION: Please help me solve this problem: A motorboat can go 14 miles downstream on a river in 20 minutes. It takes 30 minutes for this boat to go back upstream the same 14 miles. Find

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Please help me solve this problem: A motorboat can go 14 miles downstream on a river in 20 minutes. It takes 30 minutes for this boat to go back upstream the same 14 miles. Find      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 913960: Please help me solve this problem:
A motorboat can go 14 miles downstream on a river in 20 minutes. It takes 30 minutes for this boat to go back upstream the same 14 miles. Find the speed of the boat.
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
boat speed =x mph
current speed =y mph
against current 0.5 hours
with current 1/ 3 hours

Distance with current 14 miles distance against current 14
t=d/r against current (x-y)
14.00 / ( x - y )= 0.50

0.50 x - -0.50 y = 14.00 ....................1
with current (x+y)
14.00 / ( x + y )= 0.33
0.33 ( x + y ) = 14.00
0.33 x + 0.33 y = 14.00 ...............2
Multiply (1) by 0.33
Multiply (2) by 0.50
we get 2.00
0.17 x + -0.17 y = 4.62
0.17 x + 0.17 y = 7.00
0.33 x = 11.62
/ 0.33
x = 35.04 mph