Question

Find the mean of the first five even natural numbers.

Answer 1

Hint: Here we should note all the words mentioned in the question above. That are first, five, even and natural numbers. So that is the way to choose the numbers whose mean is to be found. So we will take 2,4,6,8 and 10 as the numbers whose mean is to be found.
Formula used:
Mean \[ = \dfrac{{sum{\text{ }}of{\text{ }}the{\text{ }}numbers}}{{total{\text{ }}numbers}}\]

Complete step-by-step answer:
We know that natural numbers start from 1 and are up to infinity.
But we have the condition that the number should be even. Then the numbers will be chosen from 2.
Second condition is that those are all even numbers. So, we will take 2,4,6,8 and 10 as the numbers.
Now we will use the formula to find the mean.
Mean \[ = \dfrac{{sum{\text{ }}of{\text{ }}the{\text{ }}numbers}}{{total{\text{ }}numbers}}\]
\[mean = \dfrac{{2 + 4 + 6 + 8 + 10}}{5}\]
Now on adding the numbers,
\[mean = \dfrac{{30}}{5}\]
Now divide by 5 we get,
\[mean = 6\]
This is the mean of the first five even natural numbers.
So, the correct answer is “mean = 6”.

Note: Note that the selection of the numbers is the important step. Because many times we get confused or hurry in selecting the numbers. We may take 1,2,3,4,5 as the first five natural numbers but forget the word even. And in spite of being the simplest problem we lose the marks. So carefully read the question.