Question

A recipe for salsa uses 65% tomatoes. If a batch contains 5.2 cups of tomatoes, how large is the batch of salsa.

Answer 1

so the salsa uses 65% of tomatoes, and it just so happen for that is 5.2 cups.

let's say the salsa is "x" cups, namely 100%, and we know that 5.2 cups is 65%, thus

$\bf \begin{array}{ccll} cups&\%\\ \cline{1-2} 5.2&65\\ x&100 \end{array}\implies \cfrac{5.2}{x}=\cfrac{65}{100}\implies \cfrac{5.2}{x}=\cfrac{13}{20}\implies 104=13x \\\\\\ \cfrac{104}{13}=x\implies 8=x$