SOLUTION: A motor boat goes downstream and covers a distance in 4 hours while it covers the same distance upstream in 5 hours.If the speed of the stream is 3 km/h, find the speed of the

Algebra ->  Linear-equations -> SOLUTION: A motor boat goes downstream and covers a distance in 4 hours while it covers the same distance upstream in 5 hours.If the speed of the stream is 3 km/h, find the speed of the       Log On


   

Question 702270:
A motor boat goes downstream and covers a distance in 4 hours while it covers the same distance upstream in 5 hours.If the speed of the stream is 3 km/h, find the speed of the motor boat in still water.
Answer by checkley79(3341) About Me  (Show Source):
You can put this solution on YOUR website!
D=RT
D=(R+S)*4
D=(R-S)*5
(R+3)*4=(R-3)*5
4R+12=5R-15
4R-5R=-15-12
-R=-27
R=27 MPH. FOR THE BOAT SPEED IN STILL WATER.
PROOF:
(27+3)*4=(27-3)*5
30*4=24*5
120=120