Question

What is the arithmetic mean of 2, 9, 10 and 11?​

Answer 1

Answer:

Answer:

mean = 5.5

Step-by-step explanation:

Given:

Series : 1,2,.............,9 and 10

To find : Airthemaric mean

Apply formula

\boxed{\bold{\mathsf{mean= \frac{Sum\: of \: all \: terms }{Number \: of\: terms }}}}

mean=

Numberofterms

Sumofallterms

Now to find sum of 1,2........10

Apply formula

\boxed{\bold{\mathsf{Sum \: of \: n \: numbers = \frac{ n(n+1)}{2} }}}

Sumofnnumbers=

2

n(n+1)

Put n = 10

\begin{gathered}= \frac{10(10 + 1)}{2} \\ \\ = \frac{10 \times 11}{2} \\ \\ = 55\end{gathered}

=

2

10(10+1)

=

2

10×11

=55

Put in the values in:

\boxed{\bold{\mathsf{mean= \frac{Sum\: of \: all \: terms }{Number \: of\: terms }}}}

mean=

Numberofterms

Sumofallterms

\begin{gathered}= \frac{55}{10} \\ \\ = 5.5\end{gathered}

=

10

55

=5.5

Answer we get mean = 5.5

Answer 2

Step-by-step explanation:

forst you add up all number then divide by 4because you have 4digit like 2plus 9pluse10pluse11upon 4then you write 32upon 4simplest them so your answer is 8