Arithmetic mean(4)

[tsmith93]

If the average (arithmetic mean) of a, b, c, and d is equal to the average of a, b, and c, what is d in terms of a, b, and c?

(a) a+b+c

(b) a+b+c/3

(c) 4(a+b+c)/3

(d) 3(a+b+c)/4

(e) (a+b+c)/4

[ajith]

If the average (arithmetic mean) of a, b, c, and d is equal to the average of a, b, and c, what is d in terms of a, b, and c?

(a) a+b+c

(b) a+b+c/3

(c) 4(a+b+c)/3

(d) 3(a+b+c)/4

(e) (a+b+c)/4

Arithmetic mean of a,b,c = a+b+c/3

if we add d into the mix and still arithmetic mean is the same then d should be equal to the arithmetic mean of a b and c

hence d= (a+b+c)/3

[gmatmachoman]

from the given facts:

(a+b+c+d)/4 =(a+b+c)/3

solve for d:

=(a+b+c)/3