SOLUTION: Bryan's boat travels 15 km/h in still water.He motors 140 km downstream in the same time it takes to travel 35 km upstream. What is the speed of the river?

Question 909912: Bryan's boat travels 15 km/h in still water.He motors 140 km downstream in the same time it takes to travel 35 km upstream. What is the speed of the river?
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
r*t=d
(15-c)*t=35
15*t-c*t=35
(15+c)*t=140
15*t-c*t=35
15*t+c*t=140
add
30t=175
t=175/30
t=5.83333333 5 hr 50 minutes hr
15*5.83333333+c*5.83333333=140
87.5+c*5.83333333=140
c*5.83333333=52.5
c=52.5/5.83333333
c=9.0 mph current
check
(15+c)*t=140
(15+9)*5.83333333=140
(24)*5.83333333=140
140.0=140
(15-c)*t=35
(15-9)*5.83333333=35
(6)*5.83333333=35
35.0=35
ok

RELATED QUESTIONS
Trey's boat travels 24 km/h in still water. He motors 150 km downstream in the same time... (answered by Fombitz)

The speed of a stream is 4 km/h. A boat travels 6 km upstream in the same time it takes... (answered by nyc_function)

The speed of a stream is 3 km/h. A boat travels 6 km upstream in the same time it takes... (answered by TimothyLamb)

John has a boat that will travel at the rate of 15 kph in still water. He can go upstram (answered by ankor@dixie-net.com)

Manuel has a boat that can move at a speed of 15 km/h in still water. He rides 140 km... (answered by mananth)

A boat can travel at a speed of 15 kph in still water. The boat travels 40 km downstream... (answered by mananth)

the speed of a stream is 3 km/hr. a boat travels 4 km upstream in the same time it takes... (answered by aswathytony)

A boat travels 60 km downstream in the same time that it takes to go 36 km upstream. The (answered by Paul)

Laverne's Mercruiser travels 2 km/h in still water. she motors 140km downstream in the... (answered by Paul)