Is n/15 an integer?

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Is n/15 an integer?

by mehravikas » Mon Jun 02, 2008 2:40 am
S5-25 If n is an integer, is n/15 an integer?

(1) 3n/15 is an integer.
(2) 8n/15 is an integer.


I have solved this question, but I just want to validate my approach. Please post an answer with an explanation.
Source: — Data Sufficiency |

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by amitansu » Mon Jun 02, 2008 3:24 am
B is ans here.

From 1: 3n/15 is an integer =>n is divisible by 5.That doesn't definitely say n is also divisible by 15.Insufficient.

From 2: 8n/15 is an integer=>8n should be divisible by 15 by saying that we have to see , whether 8 multiplied any no. should be a multiple of 15.
Only way it is as, when n itself is multiple of 15. Chk it by plugin values.
So sufficient.

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by mehravikas » Tue Jun 03, 2008 2:54 am
Bingo !! I thought same as you did :-)
amitansu wrote:B is ans here.

From 1: 3n/15 is an integer =>n is divisible by 5.That doesn't definitely say n is also divisible by 15.Insufficient.

From 2: 8n/15 is an integer=>8n should be divisible by 15 by saying that we have to see , whether 8 multiplied any no. should be a multiple of 15.
Only way it is as, when n itself is multiple of 15. Chk it by plugin values.
So sufficient.