SOLUTION: The riverboat can travel 80 miles downstream in 5 hours but requires 8 hours to travel and 48 miles upstream. What is the speed of the riverboat in still water, and what is the sp

Algebra ->  Sequences-and-series -> SOLUTION: The riverboat can travel 80 miles downstream in 5 hours but requires 8 hours to travel and 48 miles upstream. What is the speed of the riverboat in still water, and what is the sp      Log On


   

Question 625309: The riverboat can travel 80 miles downstream in 5 hours but requires 8 hours to travel and 48 miles upstream. What is the speed of the riverboat in still water, and what is the speed of the current?
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
The riverboat can travel 80 miles downstream in 5 hours but requires 8 hours to travel and 48 miles upstream. What is the speed of the riverboat in still water, and what is the speed of the current
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lex=speed of boat in still water
let c=speed of current
x+c=speed of boat downstream
x-c=speed of boat upstream
travel time=distance/speed
..
80/(x+c)=5
48/(x-c)=8
..
5x+5c=80
8x-8c=48
..
40x+40c=640 (mult. by 8)
40x-40c=240 (mult. by 5)
add
80x=880
x=11
5c=80-5x=80-55=25
c=5
speed of boat in still water=11 mph
speed of current=5 mph