Answer:
12
Explanation:
Average of A and B is 6
(A+B) /2 = 6
Multiply each side by 2
A+B = 12
average of X, Y, and Z is 16
(X+Y+Z)/3 = 16
Multiply each side by 3
(X+Y+Z) = 48
To find the average of all of them
(A+B+X+Y+Z)/5
replace A+B with 12 and X+Y+Z with 48
(12+48)/5
60/5 = 12