In a family of six members: P, Q, R, S, T, and U, P is the father of Q. R is the mother of Q. S is the brother of Q. T is the sister of R. U is the grandfather of Q. Who is the grandmother of Q?
In a quiz competition, Tom is ranked 10th from the top and after swapping places with another participant, he is now ranked 15th from the top. How many participants are there in total?