# Thread: Find the Cost

1. ## Find the Cost

If the sandwich costs x dollars per foot and it is y inches long, what is the cost?

I think this question is about creating an equation.

MY WORK:

Let C = cost

Let x = dollar per foot

Let y = amount in inches

C = xy

Is this correct?

2. Originally Posted by fdrhs1984
If the sandwich costs x dollars per foot and it is y inches long, what is the cost?

I think this question is about creating an equation.

MY WORK:

Let C = cost

Let x = dollar per foot

Let y = amount in inches

C = xy

Is this correct?

Thanks for showing work for this one...

However it's not right because you need to convert between inches and feet.

3. In that case, can you show me the right answer?

4. Originally Posted by fdrhs1984
In that case, can you show me the right answer?
$\displaystyle\text{Cost} = \left(x\ \frac{\text{dollars}}{\text{foot}}\right)\left(y\ \text{inches}\right)\left(\frac{1\ \text{foot}}{12\ \text{inches}}\right)$

Notice that the units cancel leaving dollars at the end.

5. After the units are removed, does this leave me with the equation
C = x(dollars)(y/12)?

6. Originally Posted by fdrhs1984
After the units are removed, does this leave me with the equation
C = x(dollars)(y/12)?
Yes and no.

If you cancel as many units as possible, then yes, that's what you get, although normally you'd put the units at the end, as in C = xy/12 dollars. If you submitted the answer C = x(dollars)(y/12) I think the teacher would see this as somewhat odd.

Removing all units just results in C = xy/12.

7. I totally get it now. Thanks. In fact, my equation and your equation are not so different.
They both produce the total cost C.