Evaluate C(8,4)
The answer is [3] 70, so C(8,4) = 70
http://www.wolframalpha.com/input/?i=8C4&a=*MC.8C4…
Good luck!
Source(s): Experience
C(8,4)=
8C4=
70
C(8,4)=8! / 4!(8-4)! = 70
C(8.4)
EXPRESSWAY
Start with 8 and count up to get a TOTAL of 4 numbers
************************************************** **** ****************
Start with 1 and count to 4
8*7*6*5
*********
1*2*3*4…………Cancel the 2*3 with the 6 and cancel the 4 with the 8 leaving a 2 on top
2*7*5
70………… ANSWER
Another example
C(6.2)
6*5
****
1*2
30/2= 15
DIFFICULT EASY
C(20,18)……could be a LONG problemgggggggggg
Unless you go to
C(20,20-18)=C(20,2)
20*19
*******
1*2
10*19=190
YOU CAN ONLY DO THIS WITH COMBINATIONS, NOT PERMUTATIONS
Shortcut P(10,3)
10*9*8……=…..720
P(12,3)………….12*11*10=………….1320
P(20,18).. GET A CALCULATOR
C(n,k) = n! / (k! (nk)!)
= 8! / (4!(8-4)!)
= 40320 / (24(24))
= 40320/576
= 70
Answer 6
see your previous issue!
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