# Which one of the following could be the plan for the course, showing the order, from first to last, in which the book...

BibianaM on September 11 at 08:45PM

The and/or rule

One of the rules in this one is the and/or rule. In general lets say that the rule is "if NOT A then R and T are chosen" the opposite of this would be "If NOT R OR T then A is chosen" so does that mean that if R is NOT chosen, but T is that A can still be chosen or do both R and T need to not be chosen in order for A to be chosen. This rule just confuses me a little on what happens when only one variable is chosen. Thank you!

Replies

Emil-Kunkin on September 13 at 02:16PM

I think your understanding is correct. The only thing that the rule bans is a scenario where N and R/T are all out. The rule tells us nothing about a scenario where n is in. If n is in, it's possible that one of or both of r and t are also in.

BibianaM on September 13 at 08:18PM

By N do you mean A?

So for example
Not A ->R + T
Not R or Not T -> A

Does it mean that both R and T DO NOT have to be included in order for A to then be included?
What if I had a scenerio where only one was included:
R was included by T was NOT..could A still be included? I think the word OR is confusing.

Emil-Kunkin on September 15 at 05:30PM

In that scenario it totally could. Remember that we only know what would happen if the sufficient condition is true. So, we know that if A is out then both r and t are in, and we know that if either r or t are out, then a is in. This tells us nothing about a scenario where r and a are in. In fact, all three could be in based on that rule.