An important question from arithmetic progression chapter as it is already asked in previous year paper of 2015 in which we have been asked to find the middle term of the AP 6, 13, 20,…..,216.
RS Aggarwal, Class 10, Arithmetic Progression, Chapter 5A, question no 17
Given,
a=6
d=13−6=7
Tn=a+(n−1)d
216=6+(n−1)7
∴n=31
If n is odd then the middle term is (n+1)/2
Middle term, =(31+1)/2=16
T16=6+(16−1)7=111.