Answer:
20% of students prefer to go to the aquarium
50% of teachers prefer to go to the aquarium 
Explanation:
1. 
8 students prefer the aquarium out of 40 students. 
Set up an equation:
Variable x = percentage of students
8/40 = x/100
Cross multiply:
8 × 100 = 40 × x
800 = 40x
20 = x
Divide: 
20%
Check your work:
40 students × 20%
Convert percentage into decimal:
40 × 0.20
8
8 students prefered the aquarium so this is correct! 
2. 
5 teachers prefer the aquarium out of 10 teachers.
Set up an equation:
Variable x = percentage of teachers
5/10 = x/100
5 × 100 = 10 × x
500 = 10x
50 = x
50% 
Check your work: 
10 × 0.50
5
Correct!