Question

The 260th term of the series a,b,b,c,c,c,d,d,d,d,e,e,e,e,e,f,f,f,f,f,f,….is:

Answer 1

series is $a,\underbrace{b,b},\underbrace{c,c,c},\underbrace{d,d,d,d},\underbrace{e,e,e,e,e}.........$

number of a = 1
number of b = 2
number of c = 3
number of d = 4
.................
..................
we know, sum of natural numbers upto n is n(n+1)/2
if we add 1 to 22 , we get = 22(22+1)/2 = 253
and 22th term in alphabet is v
after that , w
hence, next 23 terms are only w
then also , 253 to 260 we get only w
so, 260th term is w