Please help with #3 trig question

Idont understand math at all! : o( use this scenario to answer the remaining questions: brenton purchased a new bedroom set for $4,500.00. he lives in arizona and pays a 8.75% sales tax. if he made a 50% down payment and financed the rest, what amount did he finance? what is the total sales tax brenton will pay? enter your answer in currency format, round to the nearest cent. what was brenton's total amount financed? enter your answer in currency format, round to the nearest cent.

At the beginning of the day, stock xyz opened at $6.12. at the end of the day, it closed at $6.88. what is the rate of change of stock xyz? a. 1.17% b. 11.0% c. 12.4% d. 81.5%

Tommy buys a sweater that is on sale for 40% off the original price. the expression p -0.4p can be used to find the sale price of the sweater, where p is the original price of the sweater. if the original price of the sweater is 50, what is the sale price?