SOLUTION: a boat goes 180 miles downstream in the same time it can go 120 miles upstream the speed is 9 miles per hour find the speed of the boat in still water?

Question 816589: a boat goes 180 miles downstream in the same time it can go 120 miles upstream the speed is 9 miles per hour find the speed of the boat in still water?
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
boat speed x mph
current speed 9 mph
..
against current x - 9 mph
with current x + 9 mph

Distance against current 120
Distance with current 180
Time = same equate the time against with time with current
t=d/r
120 /(x- 9 )= 180 /(x+ 9 )
120 *(x+ 9 )= 180 *(x- 9 )
120 x + 1080 = 180 x -1620
120 x -180 x = -1620 + -1080
-60 x = -2700
/ -60
x= 45 mph
m.ananth@hotmail.ca

RELATED QUESTIONS
1. A boat goes 220 miles downstream in the same time it can go 180 miles upstream. The... (answered by richwmiller)

A boat goes 150 miles downstream in the same time it can go 120 miles upstream. The speed (answered by mananth)

A boat goes 280 miles downstream in the same time it can go 210 miles upstream. The... (answered by Paul)

A boat goes 540 miles downstream in the same time it can go 450 miles upstream. The speed (answered by solver91311)

A boat goes 480 miles downstream in the same time it can go 400 miles upstream. The speed (answered by Alan3354)

Hello! A boat goes 630 miles downstream in the same time it can go 540 miles upstream. (answered by Fombitz)

A boat goes 540 miles downstream in the same time it can go 450 miles upstream. The speed (answered by solver91311)

a boat goes 560 miles downstream in the same time it can go 490 miles upstream. The speed (answered by ewatrrr)

A boat goes 15 miles per hour in still water. If it can go 12 miles downstream in the... (answered by stanbon)