Find the average of all prime numbers between 4 and 15. Choose the correct choice:
A) 30  B) 4  C) 9  D) 8  E) None
Sol.   There are four prime numbers between 4 and 15.   They are 5, 7, 11, 13   âˆ´ Required average = [5 + 7 + 11 +13 / 4] = 36/ 4= 
<gadget id="calculator">36/ 4</gadget>
<output>9</output>
9   Answer 9
<result>C</result>
Find the average of all prime numbers between 4 and 15.