Question

30 seventh graders participate in school play. Of the students in seventh grade 60% are not participating, how many students are not participating?

Answer 1

45 students are not partticipating

Explanation:

Number of students that participated in school play = 30

% of students not participating = 60%

% of those participating = 100% - 60%

% of those participating = 40%

let the total number of students in 7th graders = y

Number of students that participated in school play = total number of students in 7th graders × % of those participating

30 = y × 40%

30 = y × 0.4

30 = 0.4y

divide both sides by 0.4:

$\begin{gathered} \frac{30}{0.4}\text{ = }\frac{0.4y}{0.4} \\ y\text{ = 75} \end{gathered}$

Number of students not participating = total number of students in 7th graders - Number of students that participated in school play

Number of students not participating = 75 - 30

Number of students not participating = 45