It depends on how many days a week they have to work.
Seven days a week
About 45 days a week
7 days in a week
They worked 6 days a week.
There are 5 days in a work week in most countries.
4 days a week
5-7 days a week
There are 7 days in a week but only 5 days in a business week, also called a work week.
9 days a week
as many days and hours as you want
260 days.