If the mean of $x,y,z$ is $3x$, what is the mean of $y$ and $z$?

Question

$x, y, z$ are three numbers. The mean of $x, y, z$ is $3x$. What is the mean of $y$ and $z$?

Is the answer $4x$?

If $\dfrac{x+y+z}{3}=3x$, then... – J. M. ain't a mathematician Oct 25 '11 at 16:10 — J. M. ain't a mathematician, Oct 25 '11 at 16:10

score 10 · Accepted Answer · answered Oct 25 '11 at 16:09

10

Yes. Simply write: $$ \frac{x+y+z}{3} = 3x\Rightarrow y+z = 8x\Rightarrow \frac{y+z}{2} = 4x. $$

answered Oct 25 '11 at 16:09

SBF

score 4 · Answer 2 · answered Oct 25 '11 at 16:10

4

If the mean of three numbers is $3x$, then the sum of the numbers is $9x$. ...

answered Oct 25 '11 at 16:10

Weltschmerz

2 Answers2