Bunuel wrote:
How many different 11l-letter arrangements are possible with the letters aabbbbccccc?
A. 11
B. 45
C. 90
D. 6930
E. 11!
How many different arrangements are possible with the factor of the term a^2b^4c^5 written at full length.
We have 2 a's, 4 b's, and 5 c's. Randomize the letters first to have 11! options, then we divide by 2!, 4! and 5! to eliminate duplicate choices among those 11! random selections.
\(\frac{11! }{ 2!*4!*5! } = \frac{11*10*9*8*7*6 }{ 2! *4!} = 11*10*9*7 = 990*7\)
The only possible answer is D.
Ans: D
_________________
Source: We are an NYC based, in-person and online GMAT tutoring and prep company. We are the only GMAT provider in the world to
guarantee specific GMAT scores with our flat-fee tutoring packages, or to publish student score increase rates. Our typical new-to-GMAT student score increase rate is 3-9 points per tutoring hour, the
fastest in the world. Feel free to
reach out!