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independent
- Junior | Next Rank: 30 Posts
- Posts: 17
- Joined: Sat Mar 17, 2012 2:27 pm
- GMAT Score:600
What is the sum of the different positive prime factors of 550
A: 10
B: 11
C: 15
D: 16
E: 18
This question is from the GMATprep, I used the following logic,
550 = 2x225 = 2x15x15 = 2 x 3 x 5 x 3 x 5
Since the question asks for the sum of the DIFFERENT positive prime factors I thought that I should add 2+3+5= [spoiler]C: 10[/spoiler]
But the right question is [spoiler]E: 18[/spoiler]
Now I'm confused, what is meant by different prime factors? Doesn't this mean factors that are not equal, or simply said, factors that do not repeat?
A: 10
B: 11
C: 15
D: 16
E: 18
This question is from the GMATprep, I used the following logic,
550 = 2x225 = 2x15x15 = 2 x 3 x 5 x 3 x 5
Since the question asks for the sum of the DIFFERENT positive prime factors I thought that I should add 2+3+5= [spoiler]C: 10[/spoiler]
But the right question is [spoiler]E: 18[/spoiler]
Now I'm confused, what is meant by different prime factors? Doesn't this mean factors that are not equal, or simply said, factors that do not repeat?
). Anyway, good luck with your prep
