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What is the sum of the unique prime factors of 207?

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What is the sum of the unique prime factors of 207? [#permalink] New post 05 Nov 2017, 23:27
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55% (00:20) correct 44% (00:01) wrong based on 9 sessions
What is the sum of the unique prime factors of 207?

(A) 23
(B) 26
(C) 29
(D) 69
(E) 207


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Re: What is the sum of the unique prime factors of 207? [#permalink] New post 06 Nov 2017, 06:00
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207 is twice divisible by 3 and then by 23, so that it is 207 = 3^2*23. Then, the sum of its unique prime factors is 3+23 = 26.

Answer B
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Re: What is the sum of the unique prime factors of 207? [#permalink] New post 02 Jan 2018, 06:46
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Expert's post
Bunuel wrote:
What is the sum of the unique prime factors of 207?

(A) 23
(B) 26
(C) 29
(D) 69
(E) 207


Let’s break 207 into prime factors:

207 = 23 x 9 = 23 x 3 x 3

So, the sum of the unique prime factors is 23 + 3 = 26.

Answer: B
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Re: What is the sum of the unique prime factors of 207?   [#permalink] 02 Jan 2018, 06:46
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What is the sum of the unique prime factors of 207?

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