Look at this series: 15, 15, 27, 27, ?, 39 What number should fill the blank?	Choose the correct choice from the following answers.
A) 51 B) 39 C) 23 D) 15 E) None
Explanation: In this simple addition with repetition series, each number in the series repeats itself, and then increases by 12 to arrive at the next number.   Answer: Option 39
<result>B</result>
Look at this series: 15, 15, 27, 27, ?, 39 What number should fill the blank?