What is the arithmetic mean of 50 terms of an AP with first term 4 and common difference 4 ?

What is the coefficient of mean deviation of 21, 34, 23, 39, 26, 37, 40, 20, 33, 27 (taken from mean)?

Consider the following for the next three (03) items that follow :

The algebraic sum of the deviations of a set of values x₁, x₂, x₃, ⋯, x_n measured from 100 is -20 and the algebraic sum of the deviations of the same set of values measured from 92 is 140.

What is the mean of the values?

Consider the following for the next three (03) items that follow :

The algebraic sum of the deviations of a set of values x₁, x₂, x₃, ⋯, x_n measured from 100 is -20 and the algebraic sum of the deviations of the same set of values measured from 92 is 140.

What is the algebraic sum of the deviations of the same set of values measured from 99?