If x + Y = 6, y + z = 7, and z + x = 9, the average (arithmetic mean) of x, y and z is?

A) 11/3

B) 11/2

C) 22/3

D) 11

x+y =6 …. ( i )
y+z =7 …. ( ii )
x+z =9 …. ( iii ) 
Adding ( i ) , ( ii ) and ( iii ) 
2x+2y+2z=22

Factor out 2

2x+2y+2z=22

2(x+y+z)=22

 (x+y+z)=11

Now taking Average 

 (x+y+z)/3 = 11/3

Related MCQs:
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  2. The arithmetic mean between 4 and 6 is:
  3. The average age of A, B, C, D, and E is 40 years. The average age of A and B is 35 years and the average of C and D is 42 years. Age of E is?
  4. The average of 5 quantities is 6. The average of 3 of them is 4. What is the average of remaining 2 numbers?