Question 882283
A Leisure Time Cruises riverboat travels 46 km downstream in 2 hours. It travels 51 km upstream in 3 hours. Find the speed of the boat and the speed of the stream.
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let x=speed of boat in still water
let c=speed of the stream
(x+c)=speed of boat downstream
(x-c)=speed of boat upstream
distance/speed=travel time
..
46/(x+c)=2
51/(x-c)=3
..
2x+2c=46
3x-3c=51
..
6x+6c=138 (mult. by 3)
6x-6c=102 (mult. by 2)
add
12x=240
x=20
2c=46-2x=46-40=6
c=3
speed of boat in still water=20 km/hr
speed of the stream=3 km/hr