Question 887747
Some information must be found for the extra cost.


<i>"you rent a canoe for 3 hours, you will pay $45."</i>

That is 45/3=15 dollars per hour.


<i>"The hourly rate for renting a canoe is $10 per hour."</i>

The rental cost and the hourly rate charge are not the same.


The problem description does not contain information for how the hourly cost and the rental cost are related.  You want C as a function of h; with C being the cost and h being the number of hours.  Are we supposed to assume there is a FIXED cost as part of renting the canoe?  Call this b.


You may have these two data points, (h, C).
(0, b) and (3, 45).
The slope would be in units of dollars per hour, and this must be {{{10(dollars/hour)}}}.


You have some equation, {{{highlight_green(C=10h+b)}}}.  
You know a point (3, 45) but you do not yet know b.
-
{{{C-10h=b}}}
{{{b=C-10h}}}
{{{b=45-10*3}}}
{{{b=15}}};
So the equation is {{{highlight(C=10h+15)}}}.