Problems similar to the actual GMAT

[rainbownlife]

Hi Guys
Here is my take on problem 1....

1. There is a set of characters, A B C D E F G H I J K. There are 4 character and 3 character codes to be made out of these characters. What is the ratio of the total number possibilities of the 4 character codes to the total possibilities of the 3 character codes?


Solution:
We are given a set of 11 characters {A,B,C,D,E,F,G,H,I,J,K}
4 character codes AND 3 character codes need to be made out of this set

Problem mentions the SET with 11 characters only.
Total no of ways to get 4 char code: P(11,4) + P(8,4)
Total no of ways to get 3 char code: P(7,3) + P(11,3)
(The explanation to get these is below.)
Answer is : 8:1

You can either select 4 character code first, hence P(11,4)
Now to select 3 char code, we are left with 11-4=7 chars, hence P(7,3)

On the other hand if you selected 3 letter code first then P (11,3)
To select 4 letter code, we are left with 11-3 = 8 chars, hence P(8,4)

[simbafizzle]

dont complicate it.

[vkumar]

thanks for expln.