# If Veena volunteers, then which one of the following could be true?

J on April 2, 2019

In the video explanation it says that since V is in it satisfies the rule that V or S must be in. However, the answer for this question is that F and S could volunteer as well. I understand how F could be a possibility, but how is S? You can have both V and S in at the same time? I Thought if one was in the other was out. Am I wrong in this? You can have both letters in at the same time? Likewise, you can have L and R in at the same time? (rule 4)

Jacob on April 3, 2019

Iâ€™m happy to help. Understanding the direction of the condition is absolutely crucial, for this and for many other LR and LG questions. The rule in question states:

If no S -> V.

The contrapositive of this rule is:
If no V -> S.

Notice that this is NOT the same thing as saying that if V is IN, then S is OUT. The direction is crucial! Both the rule and the contrapositive only tell us something about the situation in which either S is OUT or V is OUT.

Therefore, in question 2, when we are told that V is in, the rule referenced above does not get activated! And that is because the direction of our conditional statement always starts with either S or V not being in.

Same exact thing for rule 4.

If no R -> L.

Contrapositive:
If no L -> R.

Does that help? Let us know if this concept is not clicking, because it is absolutely crucial!