There asre 5 questiions in a question paper. In how many ways can a boy solve one or more questions?

In how many ways can 5 boys and 5 girls sit in a ring

There are three section A,B, C in a paper each section having 5 questions . In how many ways a student can solve exactly 5 questions taken at least one question from each section.

There is a question paper consisting of 15 questions. Each question has an internal choice of 3 options. In how many ways can a student attempt one or more questions of the given fifteen questions in the paper?

A question paper contain 15 questions. In how many ways can 7 questions be attempted?