Q's mother is sister of P and daughter of M. S is the daughter of P and sister of T. How is M related to T?

Explanation:-

S is te daughter of P and sister of T. So, T is the daughter of P. Now, the sister P is the daughter of M. This means that P is the son or daughter of M. Clearly, T is the grand daughter of M. So, M is the grandfather or grandmother of T.