To make one dozen cookies, the recipe requires 2- cups of flour
1 dozen cookies require = 2 1/2cups of flour
Express the mixed fraction in the fraction:
[tex]\begin{gathered} 2\frac{1}{2}=\frac{2\times2+1}{2} \\ 2\frac{1}{2}=\frac{5}{2} \end{gathered}[/tex]1 dozen cookies require = 5/2 cups of flour
Now, for 10 dozen of cookies multiply 10 by the flour required to make 1 dozen cookies
10 dozen cookies requires = 10 x 5/2 cups of flour
[tex]\begin{gathered} 10\times\frac{5}{2}=\frac{5\times5}{1} \\ 10\times\frac{5}{2}=\frac{25}{1} \\ 10\times\frac{5}{2}=25 \end{gathered}[/tex]So, 10 dozen cookies requires = 25 cups if flour
She need 25 cups of flour for the making 10 dozen cookies
Answer : b) 25 cups
