Answer:
39
Explanation:
So there are 9 values. (1 to be added). First we add them all up. And we need to add another value. So the mean is all of the values added up, divided by the number of numbers. If we add another value, then there'll be 10 values. 24x10 is, of course, 240. If you add all of the given values, you get 201. And we can easily create the equation, x+201=240, and x, or the missing value, is obviously 39.