Factor Problem: PR Manual

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Which answer to the problem below is correct?

Poll ended at Thu Feb 12, 2009 7:16 am

(d): 1; 20%

(b): 0; No votes

both (b) and (d): 4; 80%

: Total votes: 5

Uri: Master | Next Rank: 500 Posts; Posts: 229; Joined: Tue Jan 13, 2009 6:56 am; Thanked: 8 times; GMAT Score:700

Factor Problem: PR Manual

by Uri » Tue Jan 13, 2009 7:16 am

It's a problem from PR manual.

If 65x = 3^2 × 5^2 × 13, which of the following is not a factor of x?
(a)3
(b)6
(c)9
(d)13
(e)15

Official Answer: [spoiler](d)[/spoiler]

I feel that it can be both (d) or (b). What do you think?

Quote

Source: Beat The GMAT — Problem Solving | Tue Jan 13, 2009 7:16 am

Mr2Bits: Senior | Next Rank: 100 Posts; Posts: 73; Joined: Wed Jan 07, 2009 1:00 pm; Location: Tampa, FL; Thanked: 9 times; GMAT Score:630

by Mr2Bits » Tue Jan 13, 2009 8:15 am

Solve for x

65x = 9*25*13 = 2925

65x = 2925

x=45

45 cannot be divided by 6 and 13 both B and D are correct

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aj5105: Legendary Member; Posts: 1169; Joined: Sun Jul 06, 2008 2:34 am; Thanked: 25 times; Followed by:1 members

by aj5105 » Tue Jan 13, 2009 8:22 am

5*13 X = 3^2 * 5^2 * 13
X =3^2 * 5

(b) & (d)

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Uri: Master | Next Rank: 500 Posts; Posts: 229; Joined: Tue Jan 13, 2009 6:56 am; Thanked: 8 times; GMAT Score:700

Thanks!

by Uri » Tue Jan 13, 2009 10:21 am

Thanks for the replies aj5105 and Mr2Bits.

I took the approach of aj5105. But perhaps simplifying after the last step (x=45) can make things clearer, which Mr2Bits has done. Still, simplifying in the very first step is too time consuming. Once we get X=45, we can easily understand that the PR Review Manual made mistakes