Find the average of all prime numbers between 4 and 15.	Select the correct option:  A) 30  B) 4  C) 9  D) 8  E) none

Rationale: sol . there are four prime numbers between 4 and 15 . they are 5 , 7 , 11 , 13 â ˆ ´ required average = [ 5 + 7 + 11 + 13 / 4 ] = 36 / 4 = 9 answer c
Answer: C