Please help I cannot figure this one out!

Answer:
77.47%
Step-by-step explanation:
We have to use Bayes Theorem in solving this problem.
This theorem's formula is:
P(A | B) = [tex]\frac{P(A and B)}{P(B)}[/tex]
Where the " | " means "given that".
For our problem, using bayes theorem, we can write:
P(Student has lice | positive ) = [tex]\frac{P(StudentHasLice and Positive)}{P(Positive)}[/tex]
So P(Student has lice | Positive ) = [tex]\frac{0.1692}{0.2184}=0.7747[/tex]