what do the fractions of students who ordered each type of pancake tell you about the class size?

Question

billy's class is having a pancake breakfast. each student ordered one type of pancake in advance. 1/2 of the students ordered chocolate chip, 1/6 of the students ordered blueberry, 1/4 of the students ordered plain, the rest ordered strawberry. what fraction of the class ordered strawberry pancakes?

Answer 1

1/2 + 1/6 + 1/4 + x = 1

LCD is 12:

6/12 + 2/12 + 3/12 + x = 12/12

11/12 + x = 12/12

x = 1/12