25974

This is my second solution to this proplem. This solution involves aspects of my old solution that was not very good. As before I thought long and hard. I came to the solution that the T stands for a mathmatical word, so I thought hard about all the mathmatical words I knew beginning with the letter T. I came up with Triangle and Triangular. The clue is T16 therefore it probably means the 16th triangular number that is 136. Like my old soltion sugggests there is a 1 and a 6 in the answer therefore that coincides with my old thoery a triangular number with the numbers 1 and 6. So both of my theories work out to be correct. So if the children at the school followed one of my theorys they would get the correct code and be able to open the brief case.