A test consists of 6 multiple choice questions, each having 4 alternative answers of which only one is…

A test consists of 6 multiple choice questions, each having 4 alternative answers of which only one is correct. The number of ways, in which a candidate answers all six questions such that exactly four of the answers are correct, is ___________

Solution

No. of ways of giving wrong answer =3

So, required no. of ways =C46(1)4×(3)2
=15(9)=135

Asked in: JEE Main 2020 (04 Sep Shift 2)

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