Andrea and her friends love cake. Andrea has two cakes. Each of her friends is going to eat 2/3 of a cake. How many friends can Andrea serve cake to? Answer without units. *

The line containing the midpoints of the legs of right triangle abc where a(-5,5), b(1, 1), and c(3, 4) are the vertices.

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%

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.