(look at image) can i get help on #21?

Ernest is purchasing a $175,000 home with a 30-year mortgage. he will make a $15,000 down payment. use the table below to find his monthly pmi payment.

How many $20 bills do you need to have to make $280

List the sides of δrst in in ascending order (shortest to longest) if: a ∠r =x+28°, m∠s = 2x+16°, and m∠t = x+12°