For this case we can make the following rule of three:
5 points --------------> 2 days
x -----------------------> 4 days
From here, we clear the value of x.
We have then:
[tex] x =\frac{4}{2} * (5)
[/tex]
[tex] x = 2 * 5
x = 10
[/tex]
Answer:
The student's final grade will decrease about:
x = 10 points