If the average of three numbers is V If one of the numbers is Z and another is Y what is the remaining number?

Answer 1

#1="a" #2="b" #3="c" (a+b+c)/3=V if a=Z and b=Y, Z/3+Y/3+c/3=V Therefore: c/3=V/(Z/3+Y/3) c=3*V/(Z/3+Y/3)

I've encountered that on my GRE review. The given are: A. ZY - V

B. Z/V - 3 - Y

C. Z/3 - V - Y

D. 3V- Z - Y

E. V- Z - Y

if the 3rd missing letter is X, then maybe (I just guessed, so I'm not sure):

z/3+y/3+x/3=V

x/3=V -z/3 -y/3

3(x/3)=(V -z/3-y/3)3 cancel all corresponding 3's and times 3 to V

x= 3V-z-y

the answer is D.