Late answer, but whatever.
Answer:
36. There are 36 students in the class.
Explanation:
4/12 oatmeal
2/12 cinnamon
3/12 chocolate
9 peanut
The fractions added together = 9/12
This means the 9 students = 3/12 of the class
3 x 4 = 12
9 x 4 = 36
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