I think its B. False if im wrong sorry hope this helped tho :p
Answer:

B. 30
Step-by-step explanation:
First, you multiply by 5 from both sides of equation.

Simplify, to find the answer.

, which is our answer.
80-64=24
24 is 30% of 80 so a decrease of 30%
the median of her 20 students is 82.5