Question

the mean of 11 numbers is 7. one of the numbers, 13, is deleted. what is the mean of the remaining 10 numbers?

Answer 1

The mean is the average of the numbers, so if x = all 11 numbers added together, then you have the equation:

x / 11 = 7, so x = 77 (this is all of the numbers added together)

if the number 13 is removed, the equation becomes:

(77 - 13) / 10 = M    (M is the new mean)

so the new mean is 6.4