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

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