Easy
Five children are sitting in a row. S is sitting next to P but not T. K is sitting next to R who is sitting on the extreme left, and T is not sitting next to K. Who is sitting third from the left?
Step 1: Using the seating arrangement worked out above (R-K-S-P-T from left to right), position 3 from the left is occupied by S. So the child sitting third from the left is S.
Re-check your working by substituting the answer back into the original question.