SOLUTION: If the average of a and b is z, which of the following is the average of a,b,d A) 2z+c/3 B) 2z+c/2 C) z+c/2 D)2z+c /3

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: If the average of a and b is z, which of the following is the average of a,b,d A) 2z+c/3 B) 2z+c/2 C) z+c/2 D)2z+c /3      Log On


   

Question 1141369: If the average of a and b is z, which of the following is the average of a,b,d
A) 2z+c/3
B) 2z+c/2
C) z+c/2
D)2z+c /3
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
(a+b)/2=z
so 2z=a+b
the average of a, b, and I presume c, not d, is (a+b+c)/3
This is (2z+c)/3
D
Let a=8 b=4 and c=6. 2z=12
average of and b is 6 and average of all 3 is 6
(2z+c)/3=6