Answer:

4/16 or 1/4 (simplified)

Step-by-step explanation:

5/16 plus 7/16 is equal to 12/16

16/16 ( the whole class) minus 12/16

4/16

simplify

4 divded by 4 = 1

16 divided by 4 = 4

1/4

Answer:

1/4

Step-by-step explanation:

let x be the number of 11 years old

first, you need the total amount of students in the class which are not 11 years old, hence 5/16 + 7/16=3/4

then subtract to 1 , since the problem are ratio, and 1 means whole, thus 1-3/4=1/4