Find the average of all prime numbers between 10 and 30.  Choose the correct choice:
A) 30
B) 33.6
C) 39.8
D) 18.6
E) None
Sol.   There are six prime numbers between 10 and 30.   They are 11, 13, 17, 19, 23, 29   âˆ´ Required average = [11+ 13+ 17+19+ 23+ 29 / 6] = 112/ 6 = 18.6   Answer 18.6
<result>D</result>
Find the average of all prime numbers between 10 and 30.