# If you need LR help...

• 870
• :D
##### If you need LR help...
« on: September 25, 2006, 11:32:22 PM »
Feel free to ask away. I'll try to help explain why the answer is wrong/right and guide you through the reasoning as best as I can. This is good practise for both you and me.

#### umass22

• 893
##### Re: If you need LR help...
« Reply #1 on: September 25, 2006, 11:35:43 PM »
If something says "A only if B" you always map it as "A----B"? So the "only if" signals a necessary clause, and the other thing is the sufficient?

• 870
• :D
##### Re: If you need LR help...
« Reply #2 on: September 25, 2006, 11:42:44 PM »
If something says "A only if B" you always map it as "A----B"? So the "only if" signals a necessary clause, and the other thing is the sufficient?
exactly.
The a phenomena can only occur with the presence of b. B is that necessary clause.

#### n/a

• 1826
##### Re: If you need LR help...
« Reply #3 on: September 25, 2006, 11:49:19 PM »
A only if B...

If A occurs, then B must have occured as well

B can occur and still not mean A happened.

It rains only if its cloudy.

If its cloudy, its not necessarily raining, but if its raining, then its cloudy... ya see?

• 870
• :D
##### Re: If you need LR help...
« Reply #4 on: September 26, 2006, 12:12:22 AM »
A only if B...

If A occurs, then B must have occured as well

B can occur and still not mean A happened.

It rains only if its cloudy.

If its cloudy, its not necessarily raining, but if its raining, then its cloudy... ya see?

haha precisely...let's reiterate it some more...it's kinda fun.