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JEE MATHEMATICS MCQ: PERMUTATIONS

1 Easy

1 of 1

Application +4 | -1

Let

Q_{{n}}

be the number of possible quadrilaterals formed by joining vertices of an

n

sided regular polygon. If

Q_{n+1}-Q_n=20

, then value of

n

is:

View answer and explanation

Correct option: C

6

Option C (6) is correct because substituting n=6 into the equation

Q_{n+1}-Q_n=20

after expressing

Q_n

as

{}^nC_4

satisfies the equality.

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