What number is equivalent to -21

Aflute is on sale for 20% off. including the discount and 8% tax, the sales price is $216.

Tom had a total of $220 and he spent $35 on a basketball ticket . what percent of his money did he have left?

Abird on top of a 200 ft bridge tower sees a man standing on the lower part of the bridge (which is 50 ft above the ground). the angle of depression from the bird is 26 ̊. how far is the man from the base of the bridge tower? with explanation and pictures .