What is the sum of the different positive prime factors of 660?
Choose the correct choice from the following answers.
A) 5
B) 10
C) 15
D) 17
E) 21
Prime factorization of 660   =66 * 10   =6*11 * 10   =2*3 * 2*5 * 11   =2^2 * 3 * 5 * 11   Sum of the different positive prime factors of 660 = 2+3+5+11= 
<gadget id="calculator">2+3+5+11</gadget>
<output>21</output>
21   Answer 21
<result>E</result>
What is the sum of the different positive prime factors of 660?