For a group of 60 individuals, the A.M. (Arithmetic Mean) of X and Y are 64 and 57 respectively. Then theA.M.of Z = X + 2Y is

The correct answer is (c).

The arithmetic mean (AM) of a set of numbers is the sum of the numbers divided by the number of numbers. In this case, the AM of X is 64 and the AM of Y is 57. The AM of Z = X + 2Y is therefore:

AM(Z) = (AM(X) + 2AM(Y)) / 3
= (64 + 2 * 57) / 3
= 173

Option (a) is incorrect because it is the sum of the AMs of X and Y, not the AM of Z. Option (b) is incorrect because it is the AM of X minus the AM of Y. Option (d) is incorrect because it is the AM of X plus the AM of Y.