# Find the Cost

• September 6th 2010, 06:50 PM
fdrhs1984
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?

• September 6th 2010, 07:07 PM
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Quote:

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.
• September 6th 2010, 07:28 PM
fdrhs1984
In that case, can you show me the right answer?
• September 6th 2010, 08:13 PM
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Quote:

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.
• September 7th 2010, 05:17 AM
fdrhs1984
After the units are removed, does this leave me with the equation
C = x(dollars)(y/12)?
• September 7th 2010, 05:25 AM
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Quote:

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.
• September 7th 2010, 05:38 AM
fdrhs1984
I totally get it now. Thanks. In fact, my equation and your equation are not so different.
They both produce the total cost C.