The answer is A. $36.50. To find the mean add all the values together and then divide by the total number of data points. So al of the values added together would be 730 then you divide by 20.
you multiply it as you would regular numbers and then you count the places that the decimal is in front of. in this case it would be 2 numbers, then in the number you got by multiplying, move the decimal 2 places up
