Question

20! / 16! =
A. 24
B. about 16
C. 116,280

Answer 1

Do you know what factorial means, i.e. do you know what 20! translates to?

Answer 2

Yes and i figured this problem would be easy for me, but the answer i got was quite far off of my answer choices

Answer 3

so how would you represent 20! ?

Answer 4

or take a simpler one, how would you represent, say, 4! ?

Answer 5

20*19*18*17*16*15*14*13*12*11*10*9*8*7*6*5*4*3*2*1=14311182833920000

Answer 6

ok - I was only looking for the representation - not the worked out answer - but you have it correct

Answer 7

so, in your question we have:\[\frac{20!}{16!}=\frac{20*19*18*17*16*15*...*2*1}{16*15*...*2*1}\]

Answer 8

you should notice that a lot of the terms cancel out

Answer 9

this is because:\[20!=20*19*18*17*16*15*...*2*1=20*19*18*17*16!\]therefore the 16! cancels out in this fraction leaving you with just:\[20*19*18*17\]

Answer 10

do you follow?

Answer 11

Yes

Answer 12

so you should be able to get the right answer now