For the given table:
We will find the necessary score on the final exam for a student to earn an A (90%) in the class.
so,
The equation will be:
[tex]92\cdot(0.2)+95\cdot(0.3)+88\cdot(0.2)+x\cdot(0.3)=90[/tex]now, solve the equation to find x:
[tex]\begin{gathered} 64.5+0.3x=90 \\ 0.3x=90-64.5 \\ 0.3x=25.5 \\ x=\frac{25.5}{0.3} \\ \\ x=85 \end{gathered}[/tex]So, the answer will be:
The student needs a score of 85% on the final exam to earn a 90%