In order to determine the number of ways you can select 6 question to answer, use the following formula:
[tex]C=\frac{n!}{r!(n-r)!}[/tex]where,
n: total number of questions = 10
r = 6
Then, by replacing you obtain:
[tex]C=\frac{10!}{6!(10-6)!}=210[/tex]Hence, there are 210 ways you can select 6 questions to answer.
