Question

In Mrs. Austin's science class, 37.5% of the students have compleated their science project. Of the remaining students, 40% have compleated only half of their science project. If there are 32 students in Mrs. Austin's science class, how many of these students have compleated half of their science project?

Answer 1

well, we know that 37.5% have finished it, that leaves unaccounted for 100% - 37.5% = 62.5%.

now, of those 62.5% fellows only 40% have finished only half of it, how many are those?

well, what's 62.5% of 32? what's 40% of that much?

`\begin{array}c \cline{1-1} \textit{\textit{\LARGE a}\% of \textit{\LARGE b}}\\ \cline{1-1} \\ \left( \cfrac{\textit{\LARGE a}}{100} \right)\cdot \textit{\LARGE b} \\\\ \cline{1-1} \end{array}~\hspace{5em}\stackrel{\textit{62.5\% of 32}}{\left( \cfrac{62.5}{100} \right)32}\implies 20 ~\hfill \stackrel{\textit{40\% of 20}}{\left( \cfrac{40}{100} \right)20}\implies \text{\LARGE 8}`