Question

The mean of 3,5,9,x,11 is 7 then find x

Answer 1

Given.

mean=7

find x=?

mean=sum of total no./total no.

7=3+5+9+x+11/5

35=28+x

x=35-28

x=7

Answer 2

Given: Observations; mean is 7.

To find: The value of x.

Answer:

Mean is the average of the given observations.

Formula to find the mean:

$\tt Mean\ =\ \dfrac{Sum\ of\ all\ the\ observations}{Total\ number\ of\ observations}$

Observations: 3, 5, 9, x and 11.

Total number of observations: 5.

Mean = 7 [Given].

Using the values we have into the formula,

$\tt 7\ =\ \dfrac{3\ +\ 5\ +\ 9\ +\ x\ +\ 11}{5}\\\\\\35\ =\ 28\ +\ x\\\\\\35\ -\ 28\ =\ x\\\\\\7\ =\ x$

Therefore, x = 7.