We have a semester grade that is calculated as a weighted average.
We will use decimals to calculate the weighted average and then convert the result into percentage.
We will multiply each weight (0.4 for the 1st quarter grade, for example) by the Elliot's grades (0.65 for the 1st quarter, for example).
If we do this for each component, we get:
![\begin{gathered} G=0.4\cdot0.65+0.4\cdot0.8+0.2\cdot0.85 \\ G=0.26+0.32+0.17 \\ G=0.75 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/noo05iqq6tekbb85b16lw5l9vhadag5abj.png)
Elliot's grades for the semester is 0.75 or 75%.
Answer: 75%.