S1 permutations question

[weesha]

The letters of the word POSSESSES are written on 9 cards, one on each card. The cards are shuffled and four of them are selected and arranged in a straight line.

How many arrangements are there of 4 letters.
answer is 115
dont know how to do it

 

[hina]

for that u wil first have to find out how many four letter combinations can be made from the word which are:
SSSS, SSSP, SSSO,SSSE, SSPO, SSEE, SOPE, SPEE, POEE, SSEP, SSOE, SOEE.. which means there are in total 12 combinations. Now you have to find out for each arrangement how many combinations of letters can be made..
which can be done easily: SSSS =>1
SSSP=>4, SSS0=>4, SSSE=>4, SSPO=>12, SSEE=>6....and so on for all the 12 arrangemnets.. then add up the answers, you will get 115.

thats how my teacher taught it hope that helps!!

 

[weesha]

it really helped out.... thanks alot hina

 

[hina]

ur welcum!! do ask if u hav ny more doubts?? itll help me out as well