How to solve percentages math problems

Suppose investors can earn a return of 2% per 6 months on a treasury note with 6 months remaining until maturity. the face value of the t-bill is $10,000. what price would you expect a 6-month maturity treasury bill to sell for? (round your answer to 2 decimal places. omit the "$" sign in your response.)

Angles r and s are complementary. the measure of angle r is 31 degrees. which equation can be used to find angle s?

Someone me what is the area of this figure? 18m 18m 8m 16m