Can someone help me figure this out. Pleaseee ASAP

Barbara deposited $300 in the bank. if the bank pays her simple interest at the rate of 4 percent per year, how much money will she have in her account at the end of 9 months?

If there are 3.281 feet in 1 meter, how many inches are in one centimeter

In a singing competition, there are 150 participants. at the end of each round, 40% of the participants are eliminated. how many participants are left after n rounds?