Bunuel wrote:

FRESH GMAT CLUB QUESTION:

A fair six-sided dice was rolled n times. What is the value of n?

(1) The number of different possible sequences of n-digit numbers when a dice is rolled n times is 7776.

(2) If the dice has been rolled 3 times fewer, the probability of getting a 6 on every roll would have been 1/36.

We need to see if we can create an equation with only variable, n.

We'll look for an answer that gives us this information, a Logical approach.

(1) Even if we don't know that 'the number of possible sequences...' is 6^n, then we should know that this has only one solution.

That is, there is only equation that can be created from this statement and it has only one variable - n.

Sufficient.

(2) There is only one way to get a 6 on every roll so a probability of 1/36 means the total number of options is 36.

That is, at 3 less rolls the total number of possible sequences is 36.

This is almost exactly the same as (1).

Sufficient.

(D) is our answer.

_________________

David

Senior tutor at examPAL

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