A school wants to test the operation of physical and chemical experiments, and decides the test content for the candidates by drawing lots. It is stipulated that each candidate must take three physica

A school wants to test the operation of physical and chemical experiments, and decides the test content for the candidates by drawing lots. It is stipulated that each candidate must take three physical experiments (examination papers The (1) method 1 lists all possible results in the tree diagram as follows:

Method 2 lists all possible results by list method, as shown below:

? ? A b? c？ d？ ? (A，D)？ (B，D) (C，D)？ ? e？ (A，E)？ (B，E)？ (C，E)？ f？ (A，F)？ (B，F)？ (c, f) All possible outcomes of method three are as follows:

All possible results are: AD, AE, AF, BD, BE, BF, CD, CE, CF;

(2) From (1), it can be seen that each candidate has nine possible outcomes, and the possibilities are equal.

So P(A, f) = 19.