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by gsa
5165 days ago
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Sum of first n natural numbers is n(n+1)/2. The sum of the array, represented by s, is n(n+1)/2 - x + y (subtract x - the missing number and add y - the duplicated number) gives: 1: n(n+1)/2 - x + y = s Product of first n natural numbers is represented as: n! The product of the numbers in array is p. 2: p x / y = n! (multiply by x - add missing number to product and divide by y - remove duplicated number from product). |
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