in the binomial expansion of (a + b)n , the coefficient of the 4th and the 13th terms are equal to each other. find n? Share with your friends Share 10 S. Usha Rani answered this Coefficient of 4th term would be C3n and coefficient of 13th term would be C12n Given nC3=nC12We know that nCr=nCn-rSo,nC3=nCn-12Equating,3=n-12n=15 17 View Full Answer Kartik Goel answered this nC3=nC12it holds only when 3+12=nthus n=15 3 Lyra answered this thanks 0