Sum of 500

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Sum of 500

by deepoe » Thu Feb 26, 2009 3:56 am
What is the sum of the diffrent positive prime factors of 550?
OA is 18

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by DanaJ » Thu Feb 26, 2009 4:06 am
You need to start by breaking down 550 into prime factors. I usually start with the obvious factoring:
550 = 55 * 10 = (5*11) * (2*5) = 2 * (5^2) * 11. This means that you have three positive prime factors in 550: 2, 5 and 11. The sum of things you are looking for 2 + 5 + 11 = 18.