WHO participated in the computer competition

Question:

Five students A, B, C, D, and E may participate in the computer competition and determine who participated in the competition based on the following conditions:

(1) When a participates, B also participates;

(2) B and C are attended by only one person;

(3) Both C and D participate, or none;

(4) At least one of D and E participates;

(5) If e participates, both A and D participate.

 

 

Solution:

 

1. Assume that e participates. According to step 5, both A and D participate, and B and C participate. This conclusion is in conflict with Step 2, therefore, if you do not participate in the course, you are sure to participate in the course based on 4 D.

 

2. Because d Participated, C also participated according to 3, and B did not participate.

 

3. According to condition 1, if a participates, B must also participate. It is known that B does not participate, so a does not participate.