Direction: Study the given information carefully and answer the following questions.

There are six students P, Q, R, S, T and U sitting in a row facing north direction but not necessarily in the same order. All have different marks.

The mark scored by S is 18. The number of students is sitting to the left of P is equal to the number of students is sitting to the right of R. Mark of R is thrice the mark of S, who sits third to the left of Q. The sum of the mark of T and S is the mark of U who sits on the extreme right end of the row. U scored 6 marks less than R. P scored 6 marks more than S and sits third to the left of U. The difference of mark between Q and R is 12. Q score more marks than R.