SOLUTION: in the rafting situation, a boat goes 30 kilometer downstream in 75 minutes and the same distance up stream in 90 minutes, calculate the speed of the stream in kilometer per hour.
Algebra.Com
Question 328732:  in the rafting situation, a boat goes 30 kilometer downstream in 75 minutes and the same distance up stream in 90 minutes, calculate the speed of the stream in kilometer per hour. 
Answer by Fombitz(32388)   (Show Source): You can put this solution on YOUR website!
 Rate*Time=Distance
.
.
.
Let V be the speed of the raft in still water and S be the speed of the stream.
1.<--- with the stream
2.<--- against the stream
From eq.1,
From eq. 2,
Subtract the second from the first to eliminate V.
 km/min
Since there are 60 minutes in 1 hr.
kph 
RELATED QUESTIONS
A boat goes 24 km upstream and 28 km downstream in 6 hours . It goes 30 km upstream and... (answered by Paul)
A boat goes up stream 30 miles and down stream 44 miles in 10 hours. Again it goes up... (answered by ptaylor)
a boat is rowed up stream 40 km and downstream 45 km in 13 hour . it also rowed up stream  (answered by mananth)
a boat goes upstream 30 miles and downstream 44 miles in 10 hours.the next day it goes... (answered by ankor@dixie-net.com)
A boat took 1 hour and 50 minutes to go 55 km downstream and 3 hours, 40 minutes to... (answered by edjones)
Swimming downstream, a swimmer can cover 0.5 mile in 6 minutes. It takes the swimmer 30... (answered by ewatrrr,amalm06)
A boat goes 200 miles downstream in the same time it can go 150 miles up stream.  The... (answered by Paul)
Jose rode his boat 4 kilometers up a stream and then returned the same distance. The... (answered by mananth)
The speed of a boat in still water is 15 km/hr. It goes 3 km upstream and... (answered by greenestamps)