CAT (QA) PYQs

How many numbers with two or more digits can be formed with the digits $1,2,3,4,5,6,7,8,9,$ so that in every such number, each digit is used at most once and the digits appear in the ascending order?

The number of ways of distributing $15$ identical balloons, $6$ identical pencils and $3$ identical erasers among $3$ children, such that each child gets at least four balloons and one pencil, is

The number of all natural numbers up to $1000$ with non-repeating digits is