Question

If the mean of five values is 12.2 and four of the values are 13, 9, 11, and 14, find the fifth value.

Answer 1

We know the mean is the average.

The mean of a data set is found by adding all the numbers and then dividing by the number of numbers.

We know 4 of the 5 numbers.

Let the 5th number be "x".

So, from the given information, we can write an equation:

$\frac{13+9+11+14+x}{5}=12.2$

Cross multiplying and a bit of algebra will let us find the value of "x":

$\begin{gathered} \frac{13+9+11+14+x}{5}=12.2 \\ \frac{47+x}{5}=12.2 \\ 47+x=5\times12.2 \\ 47+x=61 \\ x=61-47 \\ x=14 \end{gathered}$

The fifth value is 14.

Answer14