Club meeting

In the Green club meeting, 1/3 are Grade 4, 1/5 are GRADE 5, and the rest are Grade 6, pupils. If the total attendance is 240 pupils, how many are GRADE 6?

Correct answer:

x =  112

Step-by-step explanation:

$$\begin{gathered} n=240 \\ a=\frac{1}{3}\cdot n=\frac{1}{3}\cdot 240=\frac{1\cdot 240}{3}=\frac{240}{3}=80 \\ b=\frac{1}{5}\cdot n=\frac{1}{5}\cdot 240=\frac{1\cdot 240}{5}=\frac{240}{5}=48 \\ x=n-a-b=240-80-48=112 \end{gathered}$$

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