Question bank/JEE Main/Mathematics

(If the ratio of co-efficient of three consecutive terms in
expansion of  $(1 + x)^{n}$ is $1:7:42$ then n =

A35B45C55D65

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[IMAGE] By solving equation (1) and (2) we get n = 55, r = 7

Source: Grass-G / M-08 Mathematics Paper 23 October.docx