find the sum of all three digits numbers which are divsible by 9
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Answered by
1
Answer:
the answer is 9+4+5=18is divisible by 9
Answered by
1
Answer:
first find three digit numbers in a series
Step-by-step explanation:
108,117,126......999
a=108 , d = 9, an = 999, n = ? Sn = ?
use an formula first
an = a +(n-1)d
999 = 108 (n-1) 9
999-108 = 9n - 9
891= 9n-9
891+9 = 9n
900 = 9n
n = 900/9
n = 100
now use sn formula
sn = n/2(2a +(n-1) d
sn= 100/2(2(108)+(100-1)(9)
sn = 50(216+(99)(9)
sn = 50(216+891)
sn = 50(1107)
sn = 55350
therefore
sn = 55350
n = 100
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