Question

A mathematics journal has accepted 14 articles for publication. However, due to budgetary restraints only 9 articles can be published this month. How many ways can the journal editor assemble 9 of the 14 articles for publication?

Answer 1

@SouljaBoy @ilovepanda123 @lgbasallote someone help

Answer 2

@Carniel @Callisto can someone let me know the method

Answer 3

ok, so we have 14 articles to choose from, but we only need 9
so choosing article number 1 we have 14 options, then article 2 we have 13 etc etc..

so we have 14*13*12*11*10*9*8*7*5 different selections we could make

but now we have repeated some, because i could pick the geometry article and then the differential equations article, and it would be the same choice as choosing the differential equations then geometry, so we need to divide our number by the amount of repeats which is the number of ways we can arrange 9 articles:

(14*13*12*11*10*9*8*7*5)/(9*8*7*6*5*4*3*2*1)

what we have done indirectly is used the binomial expansion to work out the number of permutations (you may/may not have heard of "n choose r"

if you want to know more perhaps have a read:
http://mathworld.wolfram.com/Combination.html

Answer 4

wrong @Mertsj

Answer 5

sorry i missed a six

Answer 6

Oh. Sorry. I thought they were publishing 2 articles.

Answer 7

(14*13*12*11*10*9*8*7*6*5)/(9*8*7*6*5*4*3*2*1)

Answer 8

2002

Answer 9

A. 726,485,760
B. 14
C. 2,002
D. 126

Answer 10

C

Answer 11

@eigenschmeigen i picked that it was wrong

Answer 12

really? maybe i misunderstand the question..

Answer 13

its a.726,485,760

Answer 14

why? please explain

Answer 15

Because apparently the order of the articles matters.