What is the answer to this question explain (picture included)

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

Name each raycalculation tip: in ray "ab", a is the endpoint of the ray.

Three numbers x, y, and z are in the ratio 2: 7: 8. if 12 is subtracted from y, then three numbers form a geometric sequence (in the order x, y–12, z). find x, y, and z. there are 2 sets.