Question

13, 15, 17, x, 20, 21; The median is 18.

Answer 1

To find the median

⇒ must define what is a median

⇒Definition of median: middle number of an ordered set

Lets look at the information given

Set when ordered: 13,15, 17,x,20,21 with median of 18

⇒ In this case, there is an even number of numbers

⇒ to find the median

⇒ must find average of two numbers closest to the middle

⇒ which are 'x' and '17' which is equal to the given median 18

Let's set up the equation:

`(x+17)/(2) =18\\x+17=36\\x=19`

Answer: x = 19

Hope that helps!