Really shit at Prob/perms/combs (2 Viewers)

[Shadowdude]

Hey shadowdude, I went to the seminar as well and it was great. One of the questions in the book, I think the one about how could a group of people be arranged in 3 rooms, might have been incorrect. In the coroneos past paper book the question is done differently and has another answer.... I think. But still, the seminar was amazing and very useful.

Just check, because I'm sure you'll find that if you compare the answers - they'll be the same.

 

[asianese]

１９８７　５ii)

Five letters are chosen from the letters of the word CRICKET. These 5 letters are then placed alongside one another to form a five letter arrangement. Find the number of distinct five letter arrangements which are possible, considering all possible choices.





C R I C K E T.

1. 2 alike, 3 different
2. All different


1. Two Cs and 3 of RIKET... 5C3 ways = 10
2. CRIKET ... 6C5 ways = 6 ways

Permutate the selections...

1. 10 * 5!/2! = 600
2. 6 * 5! = 720

Total 1320

???

Thanks

 

[bleakarcher]

１９８７　５ii)

Five letters are chosen from the letters of the word CRICKET. These 5 letters are then placed alongside one another to form a five letter arrangement. Find the number of distinct five letter arrangements which are possible, considering all possible choices.



C R I C K E T.

1. 2 alike, 3 different
2. All different


1. Two Cs and 3 of RIKET... 5C3 ways = 10
2. CRIKET ... 6C5 ways = 6 ways

Permutate the selections...

1. 10 * 5!/2! = 600
2. 6 * 5! = 720

Total 1320

???

Thanks

yeah I got this too

 

[alexobern]

i also agree with your answer