Question

find the sum of all 3digit natural number which are multiples of 11​

Answer 1

Answer:

a=110 an=990 d=11 x=2

No. of =2

an=a+(n−1)d

990=110+(n−1).11

880/11=x−1

80=x−1

x=81

Sn=[a+an]× n/2

=[110+990]× 81/2

=1100× 81/2

=550×81

=44550.

So ans is 44550.