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:
[tex]\frac{x+17}{2} =18\\x+17=36\\x=19[/tex]
Answer: x = 19
Hope that helps!
