Fill in the blank with the correct number in this number series: 1, 20, 7, 16, __, 12, 19, ?  Choices
A) 14	B) 12	C) 13	D) 15	E) 11
This is a simple alternating subtraction and addition series; The first series begins with 1 and adds 6; the second begins with 20 and subtracts 4, and so on.   Answer: 13
<result>C</result>
Fill in the blank with the correct number in this number series: 1, 20, 7, 16, __, 12, 19, ?