There are 8 questions in an examination paper and each question has an alternative the number of ways in which a student can give his answer
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There are 8 questions in paper
Since each question has an alternative the student at least attain 8/2 = 4 questions.
If student answer 4 questions
8C4 = 8!/4!4!
= 8 × 7 × 6 × 5 / 1× 2 × 3× 4
= 70
If student answer 5 questions
8C5 = 8!/5!3!
= 8 × 7 × 6/1 × 2× 3
= 56
If he answer 6 questions
8C6 = 8!/6!2!
=8×7/2
=28
If he answer 7 questions
8C7 = 8!/7!1!
= 8
If he answers 8 questions
8C8 = 1
Total no. of ways = 70 + 56 + 28 + 8 + 1
= 163
Total no. of ways = 163 .
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