Shariq Posted August 29, 2005 Share Posted August 29, 2005 What is the sum of all three digit positive integers, the sum of whose digits is a multiple of 3? 900 165150 165000 329199 328900 OA is 165150 Quote Link to comment Share on other sites More sharing options...
sumeet_rana Posted August 29, 2005 Share Posted August 29, 2005 An arithmetic Progression: 102, 105,108...999 So a = 102 l = 999 d = 3 Sum = n / 2 [a + l ] In order to find n: Tn = a + (n-1) d therefore 999 = 102 + (n-1) 3 999 = 102 + 3n - 3 999 = 99 + 3n n = 300 Using this value in the formula of Sum above Gives 165150. Quote Link to comment Share on other sites More sharing options...
Shariq Posted August 29, 2005 Author Share Posted August 29, 2005 thnx sumeet Quote Link to comment Share on other sites More sharing options...
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