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If N is a positive interger, is the units digit of N equal

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If N is a positive interger, is the units digit of N equal

by crackitpal » Thu Sep 18, 2008 1:46 pm
If N is a positive interger, is the units digit of N equal to zero?

1. 14 and 35 are factors of N
2. N = (2^5)(3^2)(5^7)(7^6)

I chose B as answer. I thought since statement 1 lists only 2 factors of N, other factors may change the units digit of N. How to approach such problems ?

QA is D.

Thanks.
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by kv_ajay » Thu Sep 18, 2008 3:50 pm
14 * 35 = 490
Any integer multiplied by 490 will have last digit of 0.
basically u can consider same for 10...

How to sovle these problems...i don't know the answer to that..i m just collecting tips ...
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by 4meonly » Fri Sep 19, 2008 1:02 am
If N is a positive interger, is the units digit of N equal to zero?

(1)
14 and 35 are factors of N
14=2*7
35=7*5
2*5 wil get 10, units digit is 0, 0 multiplied by any number will get 0.
Moreover, lst digits of 14 and 35 are 4 and 5, 4*5=20. with 0 at the end
SUFF

(2)
N = (2^5)(3^2)(5^7)(7^6)
use the same logic as above
u have 2's and 5's? they will give 10
0 multiplied by any number will get 0
SUFF


Answer D

Hope this will make sence
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