How to calculate markup including tax and discount ? i struggling on this.

Acomputer store bought a program at a cost of $10 and sold it for $13. find the percent markup

Ftara spends $219 a month for her car payment and she makes $3,200 a month, what percent of her monthly income is spent on her car payment?

Is the underlined participial phrase correctly placed or misplaced? i smelled each and every flower strolling through the garden. a. correctly placed participial phrase b. misplaced participial phrase