Q8 of 110 Page 53

Find the sum of all 3 digit natural numbers, which are divisible by 9.

Series of three digit numbers divisible by 9 is:


108, 117,………………………………999


In the A.P.


First term = 108


Last term = 999


Common difference = 9


Nth term = a + (n–1) d


⇒ 999 = 108 + (n–1)9


⇒ 891 = (n–1)9


⇒ 99 = (n–1)


⇒ n = 100


Sum of terms =


⇒ Sum of terms =


⇒ Sum of terms =


⇒ Sum of terms = 55350


More from this chapter

All 110 →
6

In an arithmetic series, the sum of first 11 terms is 44 and that of the next 11 terms is 55. Find the arithmetic series.

 7

In the arithmetic sequence 60, 56, 52, 48,…, starting from the first term, how many terms are needed so that their sum is 368?

 9

Find the sum of first 20 terms of the arithmetic series in which 3rd term is 7 and 7th term is 2 more than three times its 3rd term.

 10

Find the sum of all natural numbers between 300 and 500 which are divisible by 11.