Question

If it takes 5 1/4 cups of flour to make 4 dozen cookies, how much flour does it take to make 10 dozen cookies ?

Answer 1

If it takes 5 1/4 cups of flour to make 4 dozen cookies,

Therefore, it will take 'x' flour to make 10dozen cookies.

$\begin{gathered} 5\frac{1}{4}\text{cups of flour=4 dozen cookies} \\ x=10\text{ dozen cookies} \end{gathered}$

Cross-multiply and solve for x

$\begin{gathered} x\times4dozen\text{ cookies=}5\frac{1}{4}\text{cups of flour }\times10dozen\text{ cookies} \\ \frac{x\times4dozen\text{ cookies}}{4\text{dozen cookies}}=\frac{5\frac{1}{4}\text{cups of flour }\times10dozen\text{ cookies}}{4\text{dozen cookies}} \end{gathered}$

Hence,

$\begin{gathered} x=\frac{\frac{21}{4}\times10}{4}=\frac{\frac{210}{4}}{4}=\frac{210}{16}=13\frac{2}{16}=13\frac{1}{8} \\ \therefore x=13\frac{1}{8} \end{gathered}$

Therefore, it will take 13 1/8 flour to make 10dozen cookies.