Logical Reasoning guide pg 69 dril only if

[noort277]

Question 3 I am preplexed by the first two choices. is the term if, and only if, equivalent to only if or not.

Assuming it is then first two choices would be like this
1.good shape --> new car
2. good shape --> new car

but these are wrong if someone could clarify them for me thanks

[Misti Duvall]

Sure!

The phrase "if and only if" does not mean the same thing as just "only if." If and only if makes it a biconditional, meaning the arrow goes both ways. Only if by itself means "then" and the arrow goes just one way.

For ex:

"I will eat cookies if and only if they are chocolate" is a biconditional statement. I means BOTH if I eat cookies then they are chocolate and if they are chocolate, then I will eat them.

"I will eat cookies only if they are chocolate" is not a biconditional statement. It means only one thing: if I eat cookies, then they are chocolate.

[noort277]

Thanks. For your help.