Which account would cost less if a person were to write 20 checks in a month?

Determine whether the set of whole numbers is closed under addition. explain why the set is or is not closed. give an example.

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. if a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. what is the margin of error of the sample mean? a. 0.086% b. 0.533% c. 1.11% d. 2.22%

Christina can paint 420 square feet in 105 minutes. which unit rate describes the scenario?