The series starts from the letter ‘T’ along with the recurring pattern of a few letters. Whenever, letter ‘T’ reappears in the series, the last two letters are removed from the recurring pattern of letters and the letter ‘T’ again appears in the series. This process continues till you reach the end of the series. Let’s break the series as follows: T S R Q P O N M L T S R Q P O N T S R Q P T S R Thus, we can say that the next letter in the series is ‘T’.