Solution to 3.

 

3. Use a truth table to answer the following questions about the following 3 statements.

a) Are 1-2 consistent with 3?
b) Do any of 1-2 individually imply 3?
c) Do 1-2 jointly imply 3?

1.b->d

2.a

3.a->c

 a  b  c  d  b->d  a->c
 T  T  T  T  T  T
 T  T  T  F  F  T
 T  T  F  T  T  F
 T  T  F  F  F  F
 T  F  T  T  T  T
 T  F  T  F  T  T
 T  F  F  T  T  F
 T  F  F  F  T  F
 F  T  T  T  T  T
 F  T  T  F  F  T
 F  T  F  T  T  T
 F  T  F  F  F  T
 F  F  T  T  T  T
 F  F  T  F  T  T
 F  F  F  T  T  T
 F  F  F  F  T  T

 

a) Are 1-2 consistent with 3?

Yes. It is possible for all to be true at once. Row 1 is an example.

b) Do any of 1-2 individually imply 3?

1 does not imply 3, as can be seen by row 3 in which 1 is T and 3 is F.
2 does not imply 3, as can be seen by the same row, in which 2 is T and 3 is F.

c) Do 1-2 jointly imply 3?

No. There are rows in which 1 and 2 are both T, but 3 is F. Row 3 is an example.