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Find the sum of all 3 digit numbers which are divisible by 3 but not 6 |
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Answer»
Hello!! 3 digit number starts from 100,101.. and ends at 999. ARITHMETIC progression can be used to find all 3 digit number that is DIVISIBLE by 3 and not by 6. The 1st 3 digit number that is divisible by 3 and not by 6 is 105. The next numbers are 111,117,123.. (PREVIOUS number added with 6).The last number is 999. nth term of an arithmetic progression- tn = a + (n – 1)d where tn- nth term(999) a =the first term (105) d= common difference(6) 999=105+(n-1)6 894=(n-1)6 n=150 The addition of series is given by- Sn= n/2*(a+tn) = 1502(105+999) = 75 (1104) = 82800 . So there are only 150 3 digit numbers that is divisible by 3 and not by 6 and there addition is 82800. Hope it HELPS you... Plz mark this as brain liest answer.... |
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