Question

7. If mean of data 2, x, 3,-5, 6 is 18. Find x.​

Answer 1

Answer:

Mean of the given observations = 11

The observations are : x,x+2,x+4,x+6,x+8

Mean =

Number of observations

Sum

=

5

x+x+2+x+4+x+6+x+8

Mean =

5

5x+20

= x+4

⇒x+4=11

⇒x=7

The first three observations are: 7,9,11

Mean of three observations =

3

7+9+11

= 9

Answer 2

Answer:

Value of $x$ is $84$.

Step-by-step explanation:

To find : value of $x$ .

Given : mean of data $2, x, 3,-5, 6$  is $18$ .

Solution :

• As per given data we know that ,  mean of data $2, x, 3,-5, 6$  is $18$ .
• Average is the arithmetic mean also called as mean .  
• It is the ratio of sum of all the numbers given in data to the total number of observations.
• Formula: $Average \ or \ mean =\frac{\text { sum of all the observations }}{\text { total of observations }}$
• Here, sum of observations $= 2 + x + 3 + (-5 ) + 6 = x + 6$
• Total number of observations $= 5$
• Mean  = $18$  
• Substituting values in above formula,

       $18 = \frac{x+ 6}{5}\\\\ x + 6 = 18\times 5 \\\\ x + 6= 90\\\\ x = 90 -6\\\\ x = 84$