Absolute killer prob question (1 Viewer)

[king.rafa]

If the letters of the word gumtree and the letters of the word koala are combined and arranged into a single twelve-letter word, in how many of these arrangements do the letters of koala appear in their corect order, but not necessarily together.

 

[Drongoski]

If the letters of the word gumtree and the letters of the word koala are combined and arranged into a single twelve-letter word, in how many of these arrangements do the letters of koala appear in their corect order, but not necessarily together.

Is the answer 12!/(2! 5!) ??

 

[lolokay]

order 12 letters = 12!
but the letters from koala have to be kept in a specific order, so divide by 5!
then divide by 2! due to two e's
= 12!/5!2!

 

[Iruka]

But there are also 2 a's in koala.

 

[study-freak]

But there are also 2 a's in koala.

But the 2 a's are already put in a specific order when the order of koala was fixed, wasn't it? Not sure though..

 

[Iruka]

But if I swap the two a's around then the letters are still in the right order.
Question doesn't specify which a comes first.

 

[king.rafa]

not really a killer. just didnt think hard enuff lols

 

[lolokay]

but you still have the same arrangement

are you disagreeing with the answer of 12!/(5!*2!) ?

 

[king.rafa]

but you still have the same arrangement

are you disagreeing with the answer of 12!/(5!*2!) ?

answers rite in the book

 

[Drongoski]

not really a killer. just didnt think hard enuff lols

After it has been done it seems easy. But if u cannot think very lucidly (that means most of us) such combinatoric problems can easily make fools of us. So no need to be hard on yourself.