What single decimal multiplier would you use to decrease by 18% followed by a 19% increase?

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

Can someone answer this question for me

Which of the following graphs could represent a cubic function?