Is c = (a+b+c)/3 ?madhan_dc wrote:Does the avg (arith. mean) of a, b, c equal c?
1. c-a = c+b
2. c=0
my answer is 1.
book answer is 3 1 and 2 are sufficent.
my approach
from 1, a+b = 0
mean a+b+c/3 = 0+c/3
since c/3 cannot be equal to c i thought 1 is sufficent.
Statement 1:
c-a = c+b
=> a+b = 0, so (a+b+c)/3 = c/3
Is c/3 = c , yes, if c is 0; no, if c ≠0
Hence, Insufficient
Statement 2:
c=0 Insufficient
Combining 1 and 2 :
(a+b+c)/3 = c/3 = c , since c=0 --- Sufficient
So, the answer is C
