数学题，帮忙

1。On a purchase of $120, a store offered a payment plan consisting of $20 down payment and 12 monthly payments of $10 each.

What percent of the purchase price, to the nearest tenth of a percent, did the customer pay in interest by using this plan??--------这句话理解得有点晕

A) 16.7% B) 30% C) 75.8% D) 106.7% E) 107.5%

140-120/120=16.7%

2。If an organization were to sell N tickets for a theater production, the total revenue from ticket sales would be 20 percent greater than the total costs of the production. If the organization actually sold all but 5 precent of N tickets, the total revenue from tickets sales was what percent greater than the total costs of the production???----------深度不理解问题

A) 4% B) 10% C)14% D)15% E)18%

谢谢高手指正！