Adam V. answered • 10/04/16

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There are 13 questions total, and we are choosing 11, so this is 13 choose 11.

We can use the combination formula:

C(n,r) = n!/r!(n-r)!

= 13! / (11!*(13-11)!)

= 13! / (11!2!)

= (13 * 12 * 11!) / (11! * 2)

The 11! can be removed since it's in both the numerator and denominator:

= (13 * 12) / 2

= 78

Therefore, there are 78 different sets of questions that can be answered

Adam V.

10/04/16