Answer :

sespo
30%. You want to add up all the muffins (which is 40) and make that your denominator. then as the numerator you make it as many blueberry muffins Anna has. (which is 12) you divide 12÷40×100. and that gives you a percent of 30.
carlos2112

Answer:

[tex]\%_B_b=\frac{3}{10} =0.3=30\%[/tex]

Step-by-step explanation:

When we talk about percentages, we refer to that amount, which, proportionally, refers to a part of the total. In this sense, the total amount of muffins would equal 100%. And we need to find what is the percentage of the amount of blueberry muffins, so:

Let:

[tex]Bb=Amount\hspace{3}of\hspace{3}blueberry\hspace{3}muffins\\B=Amount\hspace{3}of\hspace{3}bran\hspace{3}muffins\\A=Amount\hspace{3}of\hspace{3}apple\hspace{3}muffins\\\%_T=Total\hspace{3}percentage=100\%\\\%_B_b=Percentage\hspace{3} of \hspace{3}blueberry\hspace{3} muffins[/tex]

[tex]T=Total\hspace{3}amount\hspace{3}of\hspace{3}muffins[/tex]

Using  cross-multiplication we can find the what percent of the muffins are blueberry:

[tex]\frac{\%_T}{\%_B_b}= \frac{Bb+B+A}{Bb} \\\\\frac{100\%}{\%_B_b} =\frac{12+20+8}{12}[/tex]

Solving for [tex]\%_B_b[/tex]

[tex]\%_B_b=\frac{12*100}{12+20+8}=\frac{1200}{40}=30\%[/tex]