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[ptraye]

This is the question and answer.

P: The percentage of stock trades that involve fraud has markedly decreased over the last ten years.

A: (The number of stock trades that involve fraud has increased of the same period.)

C: Therefore, the total number of stock trades has risen during the last decade.


I would like to know how the percent of fraud can decrease, but the total number of fraud increased. If the percent decreases, wouldn't the total number necessarily increase?

Thanks.

[noah]

This is the question and answer.

P: The percentage of stock trades that involve fraud has markedly decreased over the last ten years.

A: (The number of stock trades that involve fraud has increased of the same period.)

C: Therefore, the total number of stock trades has risen during the last decade.


I would like to know how the percent of fraud can decrease, but the total number of fraud increased. If the percent decreases, wouldn't the total number necessarily increase?

Thanks.

Thanks for the question. I'm not sure I get what you're asking completely, as your last two sentences seem to contradict each other. However, here's how I see the problem:

Imagine there were 10 fraudulent trades in 2001 and that represented 10% of all trades.

Then, in 2011 there were 20 fraudulent trades and that represented just 5% of all trades.

What would the total number of trades be in each year?

2001: 10 is 10% of 100.
2011: 20 is 5% of 400.

That make sense?

[austindyoung]

Hey Noah, I believe I understand how the assumption here fits in with the conclusion.

However, is it a required assumption? Sufficient? I guess this answer seems counter-intuitive because "fraud" has a bad connotation... or maybe it's because the assumption doesn't seem like it has to be assumed...

Looks like a Sufficient assumption though... I guess I have been used to seeing #s and %s problems for Strengthen, Weaken, and Inference Qs... Or maybe this one is different because it is a Sufficient one (if I pegged that correctly)?

Also, just ordered the MLSAT LR book- I hear it's awesome!

Thanks!

[noah]

Hey Noah, I believe I understand how the assumption here fits in with the conclusion.

However, is it a required assumption? Sufficient? I guess this answer seems counter-intuitive because "fraud" has a bad connotation... or maybe it's because the assumption doesn't seem like it has to be assumed...

Looks like a Sufficient assumption though... I guess I have been used to seeing #s and %s problems for Strengthen, Weaken, and Inference Qs... Or maybe this one is different because it is a Sufficient one (if I pegged that correctly)?

Also, just ordered the MLSAT LR book- I hear it's awesome!

Thanks!

I would say it's a sufficient assumption. We could probably figure out another way to make that premise and conclusion go together happily.

I hope you enjoy the LR book - or, more importantly, get some juicy ideas from it!