Maths Olympiad Prep

Track / Stage 3 / 254 of 260 #254 of 1964

Problem 254

AMC 10/12, early questions
Combinatorics Difficulty 3.9 Multiple choice South African Mathematics Olympiad · South Africa

How many of the integers between 9797 and 199199 are multiples of 22 or 33?

Pick one

Official solution

E Between (and including) 9898 and 200200 there are 5151 multiples of 22; between 9898 and 199199 there are 3434 multiples of 33. Between 102102 and 198198 there are 1717 multiples of 66. The number we seek is 51+3417=6851 + 34 - 17 = 68

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