Answer :
[tex]\begin{gathered} \text{Test score=80} \\ \text{ Reduction percentage =25\%} \end{gathered}[/tex]
Firstly, we are going to find the 25% of the test score which is 80.
Thus, we have:
[tex]\begin{gathered} 25\text{ \% of }80 \\ \frac{25}{100}\times80=20 \end{gathered}[/tex]Hence, the new grade is:
[tex]80-20=60[/tex]