BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

28-26

Expert replies
by magical cook » Thu Aug 30, 2007 9:15 am
If positive integer x is a multiple of 6 and positive integer y is a multiple of 14, is xy a multiple of
105?

(1) x is a multiple of 9.
(2) y is a multiple of 25.
Join the discussion
Source: — Data Sufficiency |

by kajcha » Thu Aug 30, 2007 9:51 am
IMO C
Join the discussion

by magical cook » Thu Aug 30, 2007 12:29 pm
Unfortunately answer is different.

Can anyone help?
Join the discussion

Re: 28-26

by ratindasgupta » Thu Aug 30, 2007 12:39 pm
magical cook wrote:If positive integer x is a multiple of 6 and positive integer y is a multiple of 14, is xy a multiple of
105?

(1) x is a multiple of 9.
(2) y is a multiple of 25.
if x is multiple of 6, then it has 2 and 3 as factors. y similarly has 2 and 14 as factors. so xy will atleast have 2, 3 and 7 as factors.

Now 105 has 3, 5 and 7 as factors. so for xy to be divisible by 105, xy must also contain 5 as one of its factors.

1) if x is a multiple of 9, then x is may or may not be a multiple of 5 also. and y too may or may not be a multiple of 5. So INSUFF

2) since y is a multiple of 25, y is also a multiple of 5. So xy is a multiple of 3, 5 and 7. Hence it is a multiple of 105. So SUFF.

Answer is B.
Join the discussion

by magical cook » Thu Aug 30, 2007 12:49 pm
Thank you!
Join the discussion

by ratindasgupta » Thu Aug 30, 2007 12:54 pm
Join the discussion