How do you write 139/25 as a percentage

Identify a1 and r for the geometric sequence an= -256(-1/4) n-1

Find the value of x for which the lines are parallel.

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%