If the coefficients of the (r-1)^ th , r^ th and (r+1)^ th terms in the expansion of (x+1)^n are in the ratio...

Question

If the coefficients of the (r-1)^ th , r^ th and (r+1)^ th terms in the expansion of (x+1)^n are in the ratio 2:15:70, then find the value of n.

Accepted Answer

16

JEE Main Mathematics question