The total number of numbers greater than 1000 but less than 4000 that can be formed using 0, 2, 3, 4 (using repetition allowed) are

A polygon of n sides has 105 diagonals, then n is equal to

How many factors of $$2^5 \times 3^6 \times 5^2$$ are perfect squares?

A candidate is required to answer 7 questions out of 12 questions which are divided into two groups each containing 6 questions. He is not permitted to attempt more than 5 questions from either group. The number of ways in which he can choose the 7 question is