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by vk_vinayak » Mon Aug 27, 2012 2:28 am
Which of the following fractions has the greatest number of unique decimal digits?

A. 1/9
B. 3/11
C. 4/9
D. 5/7
E. 7/8

[spoiler]OA: D[/spoiler]

Any shortcuts (or number properties) that would help us solve this without testing each option?[/i]
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by GaneshMalkar » Mon Aug 27, 2012 4:04 am
vk_vinayak wrote:Which of the following fractions has the greatest number of unique decimal digits?

A. 1/9
B. 3/11
C. 4/9
D. 5/7
E. 7/8

[spoiler]OA: D[/spoiler]
Any shortcuts (or number properties) that would help us solve this without testing each option?[/i]


My thoughts on this :-

x/9 where x is any integer will give a recurring digits after decimal so only one unique number after it so option A and option C is out...

x/11 will give utmost 2 unique digits after which it will be recurring digits

so left with option D and E

with option E divide by 8 :- Any number when divide by 8 after two iteration after decimal point(max) will come as 40 which is divisible by 8 ..>So max we can get only 3 unique numbers

Option D - Anything which is not a multiple of 7 will give a recurring set of 7 unique digits ....

Not sure if this helps....
If you cant explain it simply you dont understand it well enough!!!
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by vk_vinayak » Mon Aug 27, 2012 6:05 am
Sure, it helps.
x/11 will give utmost 2 unique digits after which it will be recurring digits
Any number when divide by 8 after two iteration after decimal point(max) will come as 40 which is divisible by 8 ..>So max we can get only 3 unique numbers
Anything which is not a multiple of 7 will give a recurring set of 7 unique digits ....
Are these three the general rules or apply only to the options that are given?
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