Knewton Prime Factorization Problem

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Jessie@Knewton: Official Company Rep; Posts: 20; Joined: Wed Jul 13, 2011 1:02 pm; Thanked: 2 times

by Jessie@Knewton » Mon Aug 01, 2011 11:54 am

What is the sum of the numbers in the prime factorization of 280? (If a prime factor appears more than once in the prime factorization, add it once for each time that it appears.)

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Source: Beat The GMAT — Problem Solving | Mon Aug 01, 2011 11:54 am

winniethepooh: Master | Next Rank: 500 Posts; Posts: 370; Joined: Sat Jun 11, 2011 8:50 pmFollowed by: 2 members; Location: Arlington, MA.; Thanked: 27 times

by winniethepooh » Mon Aug 01, 2011 11:59 am

The prime factors are 2*2*2*5*7 = 280
So, the sum = 2+2+2+5+7 = 18.

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crackinggmat: Senior | Next Rank: 100 Posts; Posts: 79; Joined: Thu Jun 03, 2010 11:58 am; Thanked: 1 times

by crackinggmat » Mon Aug 01, 2011 12:19 pm

280 = 2^3 * 5 *7
sum = 2+ 5+7 =14

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