I think the question needs some additional wording to indicate that we're talking about the DECIMAL EQUIVALENT of each fraction.

As it stands, each FRACTION has exactly 2 unique digits.

For example, 1/4 has a 1 and a 4

1/3 has a 1 and a 3

etc

Here's one way to word the original question....

SajjadAhmad wrote:

Which of the following fractions has the greatest number of unique digits in its decimal equivalent?

A 1/6

B 1/4

C 1/3

D 3/4

E 5/7

Interestingly enough, we don't even need to convert answer choice E to a decimal.

Here's why:

A 1/6 = 0.1666666... (2 unique digits)

B 1/4 = 0.25 (2 unique digits)

C 1/3 = 0.3333333... (1 unique digit)

D 3/4 = 0.75 (2 unique digits)

At this point, we know that the decimal equivalent of E (5/7) cannot have just 1 unique digit, since answer choices A, B and D would then be TIED for having the greatest number of unique digits

Likewise, the decimal equivalent of E (5/7) cannot have 2 unique digits, because that would mean answer choices A, B, D and E would then be TIED for having the greatest number of unique digits.

So, we can safely conclude that answer choice E must have the greatest number of unique digits

Cheers,

Brent

_________________

Brent Hanneson – GMATPrepNow.com

Sign up for our free Question of the Day emails