The number 4 is the smallest positive
integer that has exactly three factors:
1, 2, and 4. If k is the next-highest integer
that also has exactly three factors, what is
the sum of the three factors of k?	Choices:
A) 13  B) 14  C) 16  D) 18  E) 20
The greatest of the five possible answers is 20, so k is less than 20. Use trial and error to   find the value of k:   Factors of 5: 1 5   Factors of 6: 1 2 3 6   Factors of 7: 1 7   Factors of 8: 1 2 4 8   Factors of 9: 1 3 9   Thus, k = 9, and the sum of the factors of k is 1 + 3 + 9= 
<gadget id="calculator">1 + 3 + 9</gadget>
<output>13</output>
13.   correct answer 13)13
<result>A</result>
The number 4 is the smallest positive
integer that has exactly three factors:
1, 2, and 4. If k is the next-highest integer
that also has exactly three factors, what is
the sum of the three factors of k?