Q21 - Bank deposits are credited on

[kimjy89]

I see that one flaw the argument makes is confusing a necessary condition as a sufficient condition and I kind of see that the second flaw is to do with the placement of 'know' but I can't pinpoint what the second flaw is.

Thanks.

[ManhattanPrepLSAT1]

That's great! You may not be able to put it into words but being able to spot the flaw and duplicate it in an answer choice is good enough. I would describe the two flaws committed in the argument as

1. Mistakes a sufficient for necessary condition.
2. Assumes that Alicia is aware of the policy.

Just because she knows the deposit was made before 3pm, does not mean that she is aware of the policy outlined in the first sentence of the argument.

(A) mistakes a sufficient for necessary condition, but does not commit the second flaw where an assumption that someone is aware of a policy is made.
(B) mistakes a sufficient for necessary condition, but does not commit the second flaw where an assumption that someone is aware of a policy is made. Notice the "know" is in the policy, rather than the application of the policy.
(C) commits both flaws and is the correct answer.
(D) is a valid argument and so is incorrect. It has no conditional relationships, so does not commit the flaw of mistaking a sufficient for necessary condition. Nor does it have the assumption of knowledge; believing is contained both in the evidence and in the conclusion (thanks to timmydoeslsat for prompting me to come and temper my previous dismissal of this answer choice).
(E) commits the second flaw about "knowing" but does not mistake a sufficient for necessary condition.

Good work. Hopefully, even if you couldn't describe the second flaw, you were still able to find the correct answer by matching up some of the elements from the stimulus with the answer choices.

[aznriceboi17]

Hi, sorry to bring up an old post. But I wanted to ask: isn't one of the flaws is that a necessary condition (bank deposit made before 3 PM) is mistaken for a sufficient condition (and not the reverse)?

Maybe I'm misunderstanding the phrase, but when we say a person mistakes A for B, that means that the person thinks he/she sees B, even though what he/she is actually seeing is A, right?

[ManhattanPrepLSAT1]

Hi aznriceboi17,

You're absolutely right, though I can't think of a single question where the test asked you to distinguish between mistaking a sufficient for necessary condition and mistaking a necessary for sufficient condition. Essentially, that level of distinction is typically more than you need, but good point!

[jewels0602]

I am just curious about how to diagram the "only when" in stim. Is deposit before 3PM sufficient because of the when?

Kind of like how it is with "only if"

[WaltGrace1983]

I am just curious about how to diagram the "only when" in stim. Is deposit before 3PM sufficient because of the when?

Kind of like how it is with "only if"

"X only if/only when Y" translates to X → Y or, in other words, ~Y → ~X.

The diagram should go as follows:

Credited → bef. 3pm, bef. 3pm
Therefore,
(Knows) Credited

[jonathangroffman]

Hi,
I understand now how C is the correct answer, and perhaps I'm overthinking it, but I don't fully understand how both flaws can be true at the same time.

If for example, Alicia knows that she beat the 3pm deadline and mistakenly assumes that that means it will be credited that day, she would be aware of the deadline and therefore Flaw 2 wouldn't exist.

Or if she doesn't know about the deadline (flaw 2) then how could she be held responsible for the flaw of thinking that it'll be credited. Wouldn't it be perfectly reasonable for her to think that since she got the deposit in before the end of the business day, that it would be credited that day?

Probably overthinking but could someone weigh in?

[maryadkins]

Hmm. Not sure how to answer. You're saying if she doesn't know her assumption is flawed, she's not making another mistake. I hate using the term "overthinking" on the LSAT because in general thinking hard about these questions is good. But in this case, it ventures off course a bit because you're asking a sort of metaphysical question about the concurrent existence of things that doesn't end up being important for getting to the right answer choice. So I'd say for the purposes of this (extremely rare) question, maybe you're overthinking it.

[gonzalvj]

Hi!

I know this is an old question, but could someone explain it to me?

I am very confused about how the sufficient is being mistaken for necessary and how to find the similar flaw in the questions.

[CarolL800]

Hi,
In regards to your post, "I am very confused about how the sufficient is being mistaken for necessary," the previous responders cover it but I'll try to summarize here.

Let's try diagramming-- you know that "only when" is a necessary condition, so with this in mind:

Bank deposits are credited on date of transaction--> Made before 3PM
Made before 3PM
------------------------------
Bank deposit was credited on date of transaction (You know this is conclusion because of the conclusion indicator "So"-- "So, Alicia knows that the bank deposit was credited on the date of transaction.")


So basically, it's A--> B and then B--> A (converse/ mistaken reverse is happening).
The sufficient ("A") is being mistaken for necessary because we see it in the conclusion as B--> "A" (necessary). It's been switched up so that's one of the flaws here.

[DeidreH12]

When reading this prompt I could not, for the life of me, see the "knowledge flaw." I have always been given the advice to assume everything in the prompt as true. So, in my mind, if it says "bank deposits are credited on the date of the transactions only when they are made before 3 P.M.," then that is true. I wouldn't question it. Maybe if it was written as "Alicia believes that bank deposits... or Alicia's bank deposits are always credited...." I would question her knowledge. But not as a statement. Do i need to start questioning these things??? Thank for the help.

[Laura Damone]

You're totally right to accept the premises as true. Don't change that! Bank deposits are credited on that date, period.

But the next premise is that Alicia knows the deposit was made before 3. And the conclusion is that she knows the deposit was credited on the date of transaction. When you see any argument that bases a premise on somebody's knowledge, or that concludes somebody's knowledge, you should immediately think: Knowledge Flaw!

Consider this analogy:

You know you got a 170, and you applied to SuperAwesome Law School. Everybody with a 170 gets accepted to SuperAwesome Law School. Therefore, you know that you will be accepted to SuperAwesome Law School.

Good argument? No Way! How would you know that a 170 guarantees you admission? You're not on the admission board! Just because you know you got a 170, and a 170 guarantees admission, doesn't mean you know your admission is guaranteed.

Make sense?

In both the analogy and the bank argument, they're assuming that because there's a rule, a person impacted by the rule has knowledge of the rule. But that isn't always the case!

One more analogy for you:

You know you're driving 70 mph. The speed limit is 55. So you know you're breaking the speed limit.

Good argument? No way! You might not know the speed limit.

Hope this helps!
Laura