Three letters are taken from the word YAHOO to form 3 letter words. How many words can be made?

Question

experimentx · Answer

$$ \binom{4}{3} 3!$$

experimentx · Answer

if unique!!

anonymous · Answer

is this combinations or binomial probability?

experimentx · Answer

just combination and then permutation

anonymous · Answer

http://answers.yahoo.com/question/index?qid=20070415191301AAFEMYb

anonymous · Answer

i think that will help u

anonymous · Answer

ok thanks. but how would you know that its 4C3? since there 5 letters in YAHOO

rsadhvika · Answer

@experimentX  you missed words with teo O's

rsadhvika · Answer

im not sure...

rsadhvika · Answer

its two O's

experimentx · Answer

two O's is counted as one ... if only one O is allowed.

anonymous · Answer

oh i get it. thanks!

experimentx · Answer

if both O's are allowed, then we have 5 choices out of 3

rsadhvika · Answer

5 choices are there. but two O's cant permute, so it  should be
5c3/2!

 ?

rsadhvika · Answer

5P3/2!

rsadhvika · Answer

never mind pls i get confused easily...

experimentx · Answer

not really ... we should have different cases under different constrains as @yahoo posted the link

case 1: only one O's is allowed
case 2: both O's are allowed <--- here it's divided by 2!
case 3: no O's is allowed

anonymous · Answer

how would to tell the difference if its permutations or combinations?

experimentx · Answer

combination is just choosing 
permutation is arranging

anonymous · Answer

ok thank you!

experimentx · Answer

eg.
choose 3 people out of 5 <--- combinations
choose 3 people out of 5 and arrange them in a line <--- permutation