AAA batteries are advertised to have a life of about 9 hours of use. With certain level of confidence. It is advertised that the life is between 8 to 10 hours. If 9 hours is the point estimates then the margin of error is.

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