#12 - Leachate is a solution, frequently highly contaminated

[Lucas Moreau]

Hello, salty,

You may be overthinking this one a little bit...that's fine, though, it happens!

You are correct that answer choice E only has one half of the bidirectional conditional statement. But that would not make it invalid - it, indeed, must be true that answer choice E is correct based on the passage. Not containing additional must-be-true information isn't enough to disqualify it as a right answer.

Hope this helps,
Lucas Moreau

[salty]

Hello, salty,

You may be overthinking this one a little bit...that's fine, though, it happens!

You are correct that answer choice E only has one half of the bidirectional conditional statement. But that would not make it invalid - it, indeed, must be true that answer choice E is correct based on the passage. Not containing additional must-be-true information isn't enough to disqualify it as a right answer.

Hope this helps,
Lucas Moreau

Hi thank you for your answer. But I'd like to ask for further clarification.
So (E) must be answer because it meets at least half the condition of bidirectional conditional statement? or because even though it meets only half, since it is the only more reasonable answer choice left, (E) must be the answer?
If it must be answer because it still meets half of bidirectional conditional statement, for future reference, if I spot an answer choice that meets only half of bidirectional conditions such as this one (IF and ONLY IF) should I go for the answer provided other answer choice are less appealing?

Thank you for your help.

[BethRibet]

Hi Salty,

Think of it like this: If I said -- it is raining and it is cold, then assuming my statements are true, and you are asked what must be true, an answer choice that only says "It is cold" must be true. It would only be wrong if it also contradicted the premise, for instance by saying "it is not raining".

The fact that the answer choice does not reaffirm everything you know from the stimulus does not make it flawed, as long as it contains something that must be true, and nothing that is not true.

Hope that helps!

Beth

[olafimihan.k]

If I diagrammed the contrapositive of

Capacity exceeded lechate escapes

As

Lechate escapes (negated) capacity exceeded (negated)

Would that be a mistaken reversal or would it be correct because it's biconditional?

[Adam Tyson]

That would be correct, olafimihan.k! In a biconditional, either both things happen or neither of them does. We don't typically diagram the contrapositive of a biconditional (double arrow) statement, because its meaning is built right into the original diagram (both or neither, never just one). However, if we were to do it, we would do it exactly the way you just did. Well done! The order wouldn't matter, by the way - you could put Leachate Escapes on either side of that double arrow.

Good work!