If ${\;^{n + 2}}{C_8}\;:{\;^{n - 2}}{P_4} = 57\;:16,$ then the value of $n$ is

JEE MATHEMATICS MCQ: PERMUTATIONS

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{\;^{n + 2}}{C_8}\;:{\;^{n - 2}}{P_4} = 57\;:16,

then the value of

n

View answer and explanation

Correct option: B

Option B (19) is correct because it is the solution to the equation derived from the given ratio of combination and permutation after simplification and solving the quadratic equation.

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