Hello!
The number of members: 150.
Absent: 14%.
Present: 86%.
We can solve this exercise in two ways. I'll show you using the rule of three:
[tex]\frac{150\rightarrow100\%}{x\rightarrow86\%}[/tex]We will multiply it across:
[tex]\begin{gathered} x\cdot100=150\cdot86 \\ 100x=12,900 \\ x=\frac{12,9\cancel{00}}{1\cancel{00}} \\ x=129\text{ were present} \end{gathered}[/tex]