Seven boys M, K, C, P, S, T and U participate in a contest. All of them finish on different ranks from 1 to 7, 1 being the highest and 7 being the lowest. The rank of S is lower than K, but higher than C. The rank of T is one below U and one above P. U has the second highest rank. The rank of S is less than only four boys. C has the least rank. Whose rank is the third from the last?

U has the second highest rank. C has the least rank.

1() > 2(U) > 3() > 4() > 5() > 6() > 7(C)

The rank of S is less than only four boys.

1() > 2(U) > 3() > 4() > 5(S) > 6() > 7(C)

The rank of T is one below U and one above P.

1() > 2(U) > 3(T) > 4(P) > 5(S) > 6() > 7(C)

The rank of S is lower than K, but higher than C.

1(K) > 2(U) > 3(T) > 4(P) > 5(S) > 6() > 7(C)

Now only 'M' is remaining which can be placed on the blank space.

1(K) > 2(U) > 3(T) > 4(P) > 5(S) > 6(M) > 7(C)

According to the above arrangement, S's rank is the third from the last.