In a certain building in a business district, a newspaper
service delivers 104 papers every day to its customers, twice as
many customers have 3 papers delivered each day as have one
paper delivered, and three times as many customers have 2 papers
delivered each day as have one paper delivered. If no customer
has more than 3 papers delivered, then the number of customers who have
2 papers delivered each day is:

you can solve it backwards if you want. The only answers that make initially sense are B and E because both of them are divisible by 3. Let’s try first anwer B: So if 18 people receive 2 papers, 6 receive one paper, and 12 receive three papers. The total amount of papers would thus be: 6x1+18x2+12x3=78 people. Thus B is incorrect. Therefore E has to be the answer.
You can check if it works: If 24 people receive 2 papers, 8 receive one paper, and 16 receive three papers. Total amount of paper: 8x1+24x2+16x3=104 papers.