Question

If the mean of the scores 10, 12, x, 15, 18 is 14, then the value of 'x' is​

Answer 1

Given :-

• Scores = 10, 12, x, 15, 18
• Mean = 14

To find :-

• Value of x = ?

Solution :-

We are given 5 numbers in which one is a variable x. The mean or the average is also given as 14. For finding x, we use a particular formula and substitute the known values.

$\pink{ \boldsymbol{Mean = \dfrac{Sum \: of \: all \: observations}{Total \: number \: of \: observations} }}$

$\dashrightarrow \: \sf{mean = \dfrac{10 + 12 + x + 15 + 18}{5} }$

$\dashrightarrow \: \sf{mean = \dfrac{55 + x}{5} }$

$\dashrightarrow \: \sf{14 = \dfrac{55 + x}{5} }$

$\dashrightarrow \: \tt{55 + x = 70}$

$\dashrightarrow \: \tt{x = 70 - 55}$

$\implies \boxed{ \bf{ \red{x = 15}}}$

Therefore the value of x is 15.

KNOW MORE:

• There are 3 measures of central tendency mainly:

1. Median (middle most term)
2. Mode (most repeated frequency)
3. Mean (average)

• Mean for grouped data:

Summation (sigma) of fixi divided by summation of fi