On a table there are 12 balls of different colours. If 6 of the balls are put into a bag and one particular must be selected,how many combination of balls are there?
ans: 462
pls show clear steps.thx
combination and permutation
2010-12-05 11:47 pm
回答 (1)
2010-12-06 12:11 am
✔ 最佳答案
First of all, put the particular ball into the bag. No. of ways = 1C1
Then, select 5 balls from the rest 11 balls and put the selected ball into the bag.
No. of ways = 11C5
Total number of ways
= 1C1 x 11C5
= 1 x (11!/5!6!)
= 462
參考: micatkie
收錄日期: 2021-04-13 17:41:42
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