Question 890419
A river tour bus can travel 10 miles upstream in the same time it takes to travel 15 miles downstream. If the rivers current is 2mph what is the boats average speed in still water?
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let x=speed of boat in still water
x+2=speed of boat downstream
x-2=speed of boat upstream
..
travel time=distance/speed
{{{15/(x+2)=10/(x-2)}}}
15(x-2)=10(x+2)
15x-30=10x+20
5x=50
x=10
boats average speed in still water=10 mph