Charles deposited $900 in a new account that earns 6% simple interest. after 2 years, how much interest will she have earned?

When george started his current job, his employer told him that at the end of the first year, he would receive two vacation days. after each year worked, his number of vacation days will double up to five work weeks (25days) of payed vacation. how many vacation days will he have in 4 years