What is the lowest common denominator of the following rational expressions?

Hannah works at the mall selling book bags. she sold 35 book bags in 5 hours. how many book bags did she sell per hour?

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

Is the number 128.439 a rational number