If x+y=10z, then which of the following represents the average (arithmetic mean) of x, y, and z, in terms of z? Choose the correct choice from the following answers:
A) 4z-1
B) 3z
C) 5z
D) z/3
E) 3z/2
Pick any number like X=12, Y=18 and Z= 3 so that X+Y=10Z, now then the arithmetic mean will be   (12+18+3)/3= 
<gadget id="calculator">  (12+18+3)/3</gadget>
<output>11</output>
11. Now, just look at the answers and put the value of Z there.   (4z-1) 4.3-1=11,it can be the answer, lets check us the other options   (B) 3.3=6, no   (C) 5.3=15, no   (D) 3/3, no   (E) (3.3)/2=3, no   so the answer will be 4z-1..
<result>A</result>
If x+y=10z, then which of the following represents the average (arithmetic mean) of x, y, and z, in terms of z?