## anonymous one year ago It takes 1 pound of flour to make y cakes. The price of flour is w dollars for x pounds. In terms of w, x and y, what is the dollar cost of the flour required to make 1 cake?

1. anonymous

A. xy/w B. y/wx C. w/xy D. wx/y E. wxy

2. SolomonZelman

Lets just simply write the data for convenience: $$\large\color{black}{ \displaystyle 1{~} {\rm pound}= y{~} {\rm cakes} }$$ $$\large\color{black}{ \displaystyle {\rm }w= x{~} {\rm pounds} }$$ ------------------------------- 1 cake is ?

3. anonymous

make it up?

4. anonymous

5 cakes?

5. SolomonZelman

excuse me, the cost for 1 cake (not flour)

6. SolomonZelman

lets do it as it is: $$\large\color{black}{ \displaystyle {\rm }w= x{~} {\rm pounds} }$$ $$\large\color{black}{ \displaystyle {\rm }\frac{w}{x}= 1{~} {\rm pounds} }$$ you know that: 1 pound=y cakes and thus, $$\large\color{black}{ \displaystyle {\rm }\frac{w}{xy}= \frac{1}{y} {~} {\rm pounds}=1{~\rm cake} }$$

7. SolomonZelman

because if 1 pounds = y cakes then, 1/y pounds = 1 cake