Mathematics

A final examination requires that a student answer any 4 out of 6 questions. In…

A final examination requires that a student answer any 4 out of 6 questions. In how many ways can this be done?
  • A.
    15
  • B.
    20
  • C.
    30
  • D.
    45
Correct Answer: Option A
Explanation

The question will be answered in
(^5C_4 = frac{6!}{(6-4)!4!}\=frac{6!}{2!4!}\=frac{6times5times4!}{2times1times4!}\=15hspace{1mm}ways)