| [ QuizWit ] in KIDS 글 쓴 이(By): cecil (기파랑) 날 짜 (Date): 1994년08월18일(목) 00시40분42초 KDT 제 목(Title): Real Eelementary school level solution FFirst, please excuse my English because I have some trouble using hangul. Well, there is a REAL elementary level solution to the problem that it only involves several additions and subtractions with fractions. The problem states : Find distinct positive integers a, b, c, such that 9/10 = 1/a + 1/b + 1/c Solution: One of the fractions has to be 1/2 since 0.333.. + 0.25 + 0.2 = 0.78333.. < 0.9. So, the problem reduces to 2/5 = 1/a + 1/b; Assume c = 1/2 Then, by repeating this process ( thanks god the fraction is large enough) One of a or be has to be 2 < (a or b) < 6 Therefore we are left with 3, 4, 5 5 is can be a solution but it leads to a,b = 5 4 is not one of the solution since 2/5 - 1/4 = 3/20 Remaing choice 3 satisfies all the condition by yielding '2/5 - 1/3 = 1/15' Answer: ( 2, 3, 15 ) |