Help with Permutation Problem (Grade 11 )

[CasualKilla]

 

Edit 2: Another way to see how and why the first method works is to mentally picture the set of all valid passwords. Separate them into blocks depending on what vowels are in the first and fourth positions. So there will be 5(4) blocks in total (one for A__E__, one for A__I__, etc.). For each of these, there are 24(23) letters left to occupy the second and third positions. This is the reasoning encoded by the product 5(4)(24)(23)(9)(8).

 

 

We done sir, well F*&cking done *slow clap*, that was the stroke of genius need to blow this wide open. It is now clear that the memo was wrong.

 

This thread showed how much confusion and logic twisting can occur when people are trying to warp their method to come to a supposedly right answer. This was a truly scary experience. All hail john, our lord and savior. Hopefully some day that teacher who wrote that memo will burn for this.

Edited December 12, 2014 by CasualKilla