```Question 115867
I'M HAVING A HARD TIME FOLLOWING WHAT YOU DID, DANYELLE.  SEE IF YOU CAN FOLLOW WHAT I DID.
First, lets start by setting up the problem (identifying the unknowns and the quantities that are equal, etc.) so we know where we are at any given time as we as we proceed towards a solution:

Distance(d) equals Rate(r) times Time(t) or d=rt; r=d/t and t=d/r

Let d=distance travelled by boat (that's what the problem is asking for)
Now we know that distance walked plus distance travelled by boat equals 21 mi (we are told this in the problem)
So 21-d=distance walked

amount of time spent walking=(21-d)/2
amount of time spent in the boat=d/46
Now we are told that the above two times adds up to 5 hrs so our equation to solve is:

(21-d)/2+d/46=5   multiply each term by 46

23(21-d)+d=230 get rid of parens
483-23d+d=230  subtract 483 from each side

483-483-23d+d=230-483  collect like terms

-22d=-253  divide both sides by -22
d=11.5 mi---------------------------------distance travelled by boat
21-d=21-11.5=9.5 mi---------------------------distance walked

CK
9.5+11.5=21
21=21
also

9.5/2+11.5/46=5
4.75+0.25=5
5=5

Hope this helps---ptaylor
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