prime numbers till $$30$$ are as follows
$$2,3,5,7,11,13,17,19,23$$ and $$29$$
Hence, the mean can be calculated as below
Mean $$=$$ Sum of numbers $$/$$ Number of numbers
$$(2+3+5+7+11+13+17+19+23+29) / 10$$
We get,
$$=129/10$$
$$=12.9$$
Therefore, $$mean=12.9$$