Solution

155068

First name
Peter Cook
School
Durham Johnston
Country
Age
13
Email address
petersamuelcook@hotmail.com

I came to the conclusion that for these statements to be true x = 19.

5+15+19=39. 39 divided by 3 = 13. Leaving the mean=13.

7+9+17+19=52. 52 divided by 4 = 13. Leaving the mean=13.

Therefore since both means are the same, x=13