Solution:
From the table given, the weighted average is calculated as shown;
[tex]\begin{gathered} \frac{(\frac{88}{100}\times200)+(\frac{95}{100}\times100)+(\frac{87}{100}\times50)+(\frac{87}{100}\times150)}{200+100+50+150} \\ =\frac{(0.88\times200)+(0.95\times100)+(0.87\times50)+(0.87\times150)}{500} \\ =\frac{176+95+43.5+130.5}{500} \\ =\frac{445}{500} \\ =0.89 \\ =0.89\times100 \\ =89\text{ \%} \end{gathered}[/tex]
Therefore, the weighted average is 89%
