Question

If the mean of the data x+3, 2x+6 is 15, then the value of x is​

Answer 1

Answer:

The value of x = 7

Step-by-step explanation:

Given,

The mean of x+3, 2x+6 is 15

To find,

The value of 'x'

Recall the formula

Mean = $\frac{Sum\ of\ observations}{Total\ number\ of \ observations}$

Solution:

Here, the observations are x+3 and 2x+6

Sum of observations = x+3+2x+6 = 3x+9

Total number of observations = 2

Then, Mean = $\frac{3x+9}{2}$

Since it given that mean = 15, we have

$\frac{3x+9}{2}$  = 15

3x+9 = 15×2 = 30

3x = 30 -9

3x = 21

x = 7

∴The value of x = 7

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Answer 2

The value of x is 7

Step-by-step explanation:

Given:

mean of the data x+3, 2x+6 is 15

To find:

value of x

Solution:

We revise and use the formula for mean in this sum

As we know mean = sum of observations

                                  no. of observations

here, no of observations in the data = 2, and the mean of the data=15

Adding all the values in the formula

15 = (x+3)+(2x+6)

              2

∴ 15 = x+3 +2x+6  .........................(adding the like terms)

                 2

∴ 15 = 3x+9

             2

∴ 30 =  3x+9

∴ 30-9 =  3x

∴ 21 =  3x

∴ 3x = 21

∴ x = 21/3

∴ x = 7

Thus, the value of x is 7

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