- #1
crays
- 160
- 0
Hi guys, i have no idea how the Permutation should be used.
An example, Find the number of arrangement of all nine letters of the word SELECTION in which
a)the two letters E are next to each other
Well i can solve this, i just make the EE as one unit so 8P8
b)the two letters E are not next to each other
I don't know how i should solve this, why couldn't i take 9P9 - 8P8 . It make sense to me, take away all those that the EE are together.
Also when its 9P8 what does it means? Is it like there's 9 space and you going to put 8 things?
Because i was taught that 10C3 means 10 choose 3.
An example, Find the number of arrangement of all nine letters of the word SELECTION in which
a)the two letters E are next to each other
Well i can solve this, i just make the EE as one unit so 8P8
b)the two letters E are not next to each other
I don't know how i should solve this, why couldn't i take 9P9 - 8P8 . It make sense to me, take away all those that the EE are together.
Also when its 9P8 what does it means? Is it like there's 9 space and you going to put 8 things?
Because i was taught that 10C3 means 10 choose 3.