ANSWER:
The attendance before the increase is 4714
STEP-BY-STEP EXPLANATION:
From the statement we can propose the following equation
[tex]\begin{gathered} x\cdot(1+0.17)=5515 \\ \text{where x is attendance before the increase} \end{gathered}[/tex]solving for x:
[tex]\begin{gathered} x\cdot(1.17)=5515 \\ x=\frac{5515}{1.17} \\ x=4713.68\cong4714 \end{gathered}[/tex]