I'm a bit confused. I simply multiplied in the first case:
(3 ways to choose the first 2 letters that are the same) * (3 ways to choose the third letter) = 9
And did the same in the second case:
(4 ways to choose the first letter) * (3 ways.... the second) * (2 ways... the third)= 24
I did...
How many combinations of three letters from the letters A,A,B,B,C,C,D are ther?
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I assumed 2 cases:
1. 2 letters are the same.
2. all the 3 are different.
And found 9 forms for the first case, and 24 for the second one. As you know my answer (33) is 20 more...
Your examples clear things up.
Can you give me some more examples for the truth values of P->Q ?
I know when we have P , Q there are 4 possible truth value for p-> Q :
P Q P->Q
1. T T T
2. T F F
3. F T T
4. F F T
Fore...
In the statement P -> Q , Q is necessary for P.
I just don't get it ,why don't we say P is necessary for Q, can you illustrate it in an example ? :redface:
No ,no ,.....
I meant, can stat provide me with a number that indicates which one of the books I must read at the moment to finish all the books at a (nearly) certain time ?
In other word ,...
Forget it.
Stat had better stay at the books and the exams, not in the real life situations.
A number !!
I am going to read 10 books in a certain period of time. The number of pages of the books varies between 40 and 1000 pages.
I need to finish them in almost the same time, so I must read each book with a certain rate.
What I need is a number to indicate the priority of each book...