<PRE><B>Question 141774</B>
Distance(d) equals Rate(r) times Time(t) or d=rt;  r=d/t and t=d/r
Let r=speed of the boat in still water
And let x=rate (speed) of the current
Going upstream we need to subtract the speed of the current:  going downstream we need to add the speed of the current
Then speed upstream =r-x=5/(5/6)
5/(5/6): multiply numerator and denominator by 6/5 to get rid of the complex fraction and we get 6
So, r-x=6--------------------------------------eq1
And speed downstream=r+x=5/(1/2)=10
and r+x=10------------------------------------eq2

add eq1 and eq2
2r=16  divide both sides by 2
r=8 mph-----------------------------speed of boat in still water

substitute r=8 into eq1
8-x=6  subtract 8 from each side

8-8-x=6-8 collect like terms

-x=-2  divide each side by -1
x=2 mph------------------------------speed of current

CK
5 =6*(5/6)
5=5
and
5=10*(1/2)
5=5


Hope this helps---ptaylor



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