Mr. plum's math class of 25 students had an average of 85 on a test. miss scarlett's class of 22 students had an average of 87 on the same test. what is the average of the two classes combined?

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%

Solve the equation by completing the square. x^2+2x=17

Afamily has five members. a mom, a dad, two sisters, & a brother. the family lines up single file. what is the probabillity that the mom is at the front of the line