Question

find the mean of first ten prime numbers

Answer 1

The first 4 prime numbers are 2,3,5,7,11,13,17,19, 23 and 29.
Mean is the average and it can be calculated by the formula,
Mean = sum of all observations/no. of observations.
Can you proceed keeping this in mind or do u need further assistance? 

Answer 2

2,3,5,7,11,13,17,19,23,29 are first ten prime numbers

mean = sum of the numbers/ total numbers
 = (2+3+5+7+11+13+17+19+23+29)/10
=129/10
=12.9