Combinations answer check please

12345678

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'A bag contains 20 chocolates 15 Toffees and 12 Peppermints. If three sweets are chosen at random, what is the probability that they are all not chocolates'

Total number of sweets = 20 + 15 + 12 = 47

P(all chocolates) = 20C3 / 47C3 = 1140 / 16215 = 0.070

So to answer this question, my thinking was to take away P(all chocolates) from 1...

1 - 0.070 = 0.93

I've also searched this question on the internet and others have got 0.93, but the answer in the textbook is 0.180

If anybody can say if my answer is right, or what I have done wrong it will be appreciated- Cheers :)
 
'A bag contains 20 chocolates 15 Toffees and 12 Peppermints. If three sweets are chosen at random, what is the probability that they are all not chocolates'

Total number of sweets = 20 + 15 + 12 = 47

P(all chocolates) = 20C3 / 47C3 = 1140 / 16215 = 0.070

So to answer this question, my thinking was to take away P(all chocolates) from 1...

1 - 0.070 = 0.93
"Not (all chocolates)" is not the opposite of "all (not (chocolates))". For instance, "one chocolate and two peppermints" falls within "not (all chocolates)", but certainly does not fulfull "all (not (chocolates))".

I've also searched this question on the internet and others have got 0.93...
What was the exact text of the exercise that these "others" were answering? ;-)
 
Thank all for the reply's- Dennis I was wondering where you get 27/47 from?
 
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