There are 16 boys in the school choir. the choir has 88 members in all. which equation, when solved, will show how many girls are in the school choir?

How do you solve a question like this?

Find the greatest common factor of the followig monomials 21u^5v,3u^4v^6, and 3u^2v^5

Ana earns 2.5% simple interest on $2,000 in her savings account. she does not make any deposits or withdrawals. after 3 years, how much interest will ana have earned on her savings account?