Over the past ten years, the town's population doubled in size. the population is currently 12,000. what was the population ten years ago? which of the following represents the given word problem if "p" represents the population ten years ago?

a) 2(p + 10) = 12,000
b) 2p = 12,000
c) p = 2(12,000)

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%