Question

in a class, 2/3 of the pupils are boys. If there are 15 more boys than girls, how many pupils are there in the class (use equation method)

Answer 1

Step 1:

Let the number of pupils = n

`\begin{gathered} Number\text{ of boys = }(2)/(3)n \\ Number\text{ of girls = }(2)/(3)n\text{ - 15} \end{gathered}`

Step 2:

Write an equation to find the value of n

`\begin{gathered} (2)/(3)n\text{ + }(2)/(3)n\text{ - 15 = n} \\ (4n)/(3)\text{ - n = 15} \\ \frac{4n\text{ - 3n}}{3}\text{ = 15} \\ (n)/(3)\text{ = 15} \\ \text{n = 15 }*\text{ 3} \\ \text{n = 45} \end{gathered}`

Final answer

There are 45 pupils in the class.