Quantcast
Channel: GMAT Club Forum - Forums > Problem Solving (PS)
Viewing all articles
Browse latest Browse all 462833

GMAT Club Tests | Re: M40-44

$
0
0
How does this solution include the odd factors like 1 or 3 or 5 or 7 or 9 or 1*3, 1*5,etc?
Bunuel wrote:
OfficialSolution:

If one of the positive factors of\(10!\) is picked at random, what is the probability that it will be odd?

A.\(\frac{1}{8}\)
B.\(\frac{1}{9}\)
C.\(\frac{1}{10}\)
D.\(\frac{1}{11}\)
E.\(\frac{1}{12}\)


To determine the probability, first calculate the highest power of 2 in\(10!\) by summing the quotients of 10 divided by powers of 2. This is computed as\( \frac{10}{2} + \frac{10}{4} + \frac{10}{8} = 5 + 2 + 1 =8\) . Therefore,\(10!\) includes a factor of\(2^8\) .

Now, consider that EACH odd factor of 10! can be combined with powers of 2, ranging from\(2^0\) , which is 1, to\(2^8\) . This results in 9 possible combinations for each oddfactor:

\( \text{(odd factor)}*2^0, \ \text{(odd factor)}*2^1, \ \text{(odd factor)}*2^2, \ ..., \ \text{(oddfactor)}*2^8\).

Among these combinations, only the first one,\( \text{(oddfactor)*1}\) , is odd. Thus, the probability of selecting an odd factor from the factors of
...

Statistics : Posted by unicornilove • on 31 Dec 2023, 09:20 • Replies 2 • Views 474



Viewing all articles
Browse latest Browse all 462833

Latest Images

Trending Articles



Latest Images