



 
Hi Jackie, The units tell you what to do. You have dollars per hour, square feet per hour and you want dollars per square foot. That is you have \[\frac{\$}{hr}, \frac{\mbox{ square feet}}{hr} \mbox{ and you want } \frac{\$}{\mbox{square foot}}.\] But if you have \[\frac{\$}{hr} \times \frac{hr}{\mbox{ square foot}}.\] Then the hours cancel and you have \[\frac{\$}{\mbox{ square foot}}.\] Hence \[12 \frac{\$}{hr} \times \frac{1}{750} \frac{hr}{\mbox{ square foot}} = \frac{12}{750} \frac{\$}{\mbox{ square foot}}.\] I hope this helps,  


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