Question

Double check for me please?
How many permutations are there for the letters in the word PARALLEL?

a. 3360

b. 6720

c. 10,080

d. 40,320
my answer: a. 3360...
Can you please explain too? Thanks!

Answer 1

what is a permutation?

Answer 2

I don't really know how to explain it... hahaa sorry! that's why i need help lol

Answer 3

you have the correct answer since it should be (8!)/(3!*2!) = 3360

Answer 4

\(\Large \color{Black}{\Rightarrow {9! \over 3!2!} }\)

9! ways to arrange all letters.
Since there are 3 l's and 2 a's and they don't distinguish, we divide by 3! * 2!

Answer 5

a permutation is the number of possible arrangements in a list of numbers, letters or whatever
eg find number of permutation of 2 out of for the letters abc
there are 6 :- ab ac bc ba ca cb and its calculated by 3*2*1 = 6
3*2*1 is rotten as 3!

Answer 6

Basically there are 8! ways to arrange 8 letters

But there are 3 copies of L, so you have to divide by 3!

There are also 2 copies of A, so you have to also divide by 2!

You do these divisions to correct for the overcounting

Answer 7

So 3360 (answer a) is the correct answer then??

Answer 8

yes

Answer 9

Yay!!!! Thanks!!

Answer 10

I meant 8! sorry