Prime no: its only divided by $1$ and exactly only by itself .
We all know that,
The first $10$ prime numbers are:
$2,3,5,7,9,11,13,17,19,23,29$
Whereas ‘n’ is the total numbers
$N=10$
Then,
$\bar{x}=(x1+x2+…xn)/n$
$\bar{x}=(2+3+5+7+11+13+17+19+23+29)/10$
$\bar{x}=129/10$
$\bar{x}=12.9$
Hence, it mean that the first $10$ prime numbers is $12.9$.