Question

There is a group of student,1/3 are in elementary ,1/2 are in middle school and 15 are in high school. How many are in the group?

Answer 1

1/2 + 1/3 = 3/6 + 2/6 = 5/6
we have 5/6 so 15 is 1/6 of the entire group
15 × 6 = 90