Question

12.5,-10,-7.5,x;the mean is 11.5

Answer 1

Answer:

Hi!

The correct answer is x = 51.

Step-by-step explanation:

By definition the mean formula is:

$mean = \frac{x_1 + x_2 + x_3 + ... + x_n}{n}$

where x are the samples of the data set and n the numbers of elements in the set.

In this case:

• n = 4
• mean = 11.5

Replacing the data on the general formula:

$11.5 = \frac{12.5 - 10 - 7.5 + x}{4}$

Solving the equation step by step,

$4 * 11.5 = -5 + x}$

$46 = -5 + x}$

$51 = x}$

Answer 2

To find X I like to average backwards: so Multiply 11.5 by 4 =46. Subtract 12.5, -10, and -7.5 =51. X=51. Then check by adding 12.5, -10, -7.5, and 51 then divide by 4 and you get 11.5 :)