Question

Find the sum of three digit number which are divisible by 11

Answer 1

STEP BY STEP EXPLANATION

a=110

d=11

an=990

n=?

A.T.Q

an=a+(n-1)d

990 =110+(n-1)11

990-110=(n-1)11

880=(n-1)11

88+1=n

89=n

Sn=n/2[2a+(n-1)d]

=89/2[2*110+(88)11]

=89/2[220+968]

=89/2[1188]

=89*594

=52866