Question

There are 42 students in a class and $\frac{5}{7}$ of the students are boys. How many girls are there in the class?

Answer 1

Number of boys in the class = $\frac{5}{7}$ of the total no. of students
=$\frac{5}{7}$ $\times$ 42 = $\left(\frac{5\times 42}{7}\right)=5\times 6=30$

∴ Number of girls in the class = 42 − 30 = 12

Hence, there are 12 girls in the class.