Question

Find the sum of all 3 digits number which are multiple of 11

Answer 1

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The lowest 3 digit multiple of 11 is 110.
And the highest is 198.

Thus, sum of all 3 digits number which are multiple of 11 are
= 5 ( 110 + 198)
= 5 * 308
= 1540.

Hope this helps,.

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Answer 2

Answer:

a=110,d=11,an=990

Step-by-step explanation:

an=a+(n-1)d

990=110+(n-1)11

n-1)11=990-110

n-1=880/11

n=81

sn=n/2(a+l)

sn=81/2(110+990)

  =81/2*1100

  =81*550

   =44550