# Thread: Have the MEAN, Need the 5th number!

1. ## Have the MEAN, Need the 5th number!

Here's the questions we need to answer and can't figure it out....

"The mean of 5 numbers is 27. Four of the numbers are 24, 33, 27 and 31. What is the fifth number?

Can you help us figure this out????

Thanks

2. Originally Posted by tiehen
Here's the questions we need to answer and can't figure it out....

"The mean of 5 numbers is 27. Four of the numbers are 24, 33, 27 and 31. What is the fifth number?

Can you help us figure this out????

Thanks
do you know what "mean" means? it is the arithmetic average. it is the sum of all the numbers divided by the number of numbers there are. thus, if we let the fifth number be $x$, we must have

$27 = \frac {24 + 33 + 27 + 31 + x}5$

now solve for $x$