What is the average (arithmetic mean) of x, y, and z?

Question

(1) —x − 4y + 3z = 14

(2) 5x + 8y + z = 26

chetan2u · Answer

We are looking for X+y+z..
Each statement gives us three variables,so each is not sufficient..

By looking at the two equations together we can see that the adding up will give us something in terms of what we are seeking..
So add the two statements..
5x+8y+z-x-4y+3z=26+14.....4x+4y+4z=40.....x+y+z=10..
Average is 10/3
Sufficient

C

Archit3110 · Answer

#1:
values of x,y,z not given
in sufficient
#2:
values of x,y,z not given
in sufficient

combining 1 & 2 
we can determine x,y,z 
sufficienet
IMO C

KanishkM · Answer

To find: x+y+z / 3 -------(a)

from 1, When we substitute for x in (a), we cannot get a value for y and z

x = - (14+4y-3z)

-3y+4z/3

from 2, When we substitute for z in (a), we cannot get a value for x and y

26 - 4x -7y/3

But when we combine both the statements, we can get the value of

just add 1 and 2 
4x + 4y + 4z = 40

x+y+z as 10

Average becomes 10/3

C

What is the average (arithmetic mean) of x, y, and z?

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GMAT Data Sufficiency (DS) Questions

What is the average (arithmetic mean) of x, y, and z?

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