There are 24 students in a class. 2 have three or more siblings. half have two siblings. one-third have one sibling, and the rest are only children. how many are only children?

24-2=22-1\2=11-1\3=10.666666... the rest are 10.666666 as CHILDREN

if you are saying purchasing 3 social media ads and one newspaper ad counts as one purchase then there are:

6 purchases

if you are asking how many of each then:

18 social media ads

6 newspaper ads