+193 If x is the average (arithmetic mean) of m and 9, y is the average of 2m and 15, and z is the average of 3m and 18, what is the average of x, y, and z in terms of m?
A) m+6
B) m+7
C) 2m+14
D) 3m+21
+37146 I come up with m+7
(x+y+z)/3 is the average....sub in the values given for x y and z
([9 +m +2m+15 + 3m+18] /2 )/3 = ( (6m + 42)/2) / 3 = (3m+21)/3 = m+7
