SOLUTION: A man rows 18 miles downstream in 2 hours. He finds that it takes 8 hours to row back. Find the rate of the rowing to still water and the rate of the streets please show steps!

Question 539541: A man rows 18 miles downstream in 2 hours. He finds that it takes 8 hours to row back. Find the rate of the rowing to still water and the rate of the streets
please show steps! it'd help a lot, thanks :D
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
Boat speed =x mph
current speed =y mph
against current x-y 8.00 hours
With current x+y 2.00 hours

Distance = same= 18 miles
t=d/r
18 / ( x - y )= 8.00
8 ( x - y ) = 18.00
8 x -8 y = 18 ....................1
18 / ( x + y )= 2.00
2.00 ( x + y ) = 18
2.00 x + 2.00 y = 18 ...............2
Multiply (1) by 1.00
Multiply (2) by 4.00
we get
8 x + -8 y = 18
8 x + 8 y = 72
16 x = 90
/ 16
x = 5.63 mph

plug value of x in (1)
8 x -8 y = 18
45 -8 y = 18
-8 y = 18 -45
-8 y = -27
y = 3.38 mph
Boat 5.63 mph
current 3.38 mph
m.ananth@hotmail.ca
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