How do I do this? Can anyone help?

The standard deviation for a set of data is 5.5. the mean is 265. what is the margin of error?

Tom is the deli manager at a grocery store. he needs to schedule employee to staff the deli department for no more that 260 person-hours per week. tom has one part-time employee who works 20 person-hours per week. each full-time employee works 40 person-hours per week. write and inequality to determine n, the number of full-time employees tom may schedule, so that his employees work on more than 260 person-hours per week. graph the solution set to this inequality.

How can (square root of 25) ^2 be rewritten?