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Permutations and Combinations question

2024 · 6 Apr · Shift 2 · Q47

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PYQ Library
JEE Main
Mathematics
Permutations and Combinations
2024 · 6 Apr · Shift 2 · Q47

Permutations and Combinations question

2024 · 6 Apr · Shift 2 · Q47

JEE MainMathematicsPermutations and CombinationsMCQ+4 / −1

Let

0 \leq r \leq n

. If

{ }^{n+1} C_{r+1}:{ }^n C_r:{ }^{n-1} C_{r-1}=55: 35: 21

, then

2 n+5 r

is equal to :

A
62
B
60
C
55
D
50

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