Q4 of 50 Page 32

Find the sum of all three digit numbers, which are multiples of 9.

Three digit numbers which are multiples of 9 are in AP


The sequence is 108,117..999


a = 108


an = 999


d = 9


an = a + (n-1)×d


999 = 108 + (n-1)× 9


∴ n = 100


Sn =


=


= 50× 1107


= 55350


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