Any good garden compost may appropriately be used for soil drainage and fertility. The best compost is 40 to 60 perce...

shunhe on July 30, 2020

Hi @hkolon,

Thanks for the question! So let’s take a look at the stimulus. We’re first told that any good garden compost may appropriately be used for soil drainage and fertility. Well, this is something we can diagram; it just means that if it’s good garden compost, we can appropriately use it for soil drainage and fertility. So that’s diagrammed as

Good garden compost (GGC) —> May be used for soil drainage and fertility (MBUSDF)?
Now the next sentence tells us that the best compost is 40-60% organic matter and dark brown in color. So we can diagram that as

Best garden compost —> 40-60% organic matter & dark brown in color

Then, we’re told that compost that emits a strong ammonia smell shouldn’t be used for drainage and fertility. So if it emits a strong ammonia smell, it shouldn’t be used, we can diagram that

Strong ammonia smell (SAS) —> ~MBUSDF

Now we’re asked for something that’s most strongly supported; in other words, this is a must be true question. We’re given a group of facts here as opposed to an argument with a conclusion, so we have to be able to directly infer something from a fact, or combine facts to get to something. And we can immediately see here that some of the facts can be combined, so it’s good to keep those combinations i mind. Since we know that SAS —> ~MBUSDF, we can take the contrapositive of the first statement to get

~MBUSDF —> ~GGC

which lets us know that

SAS —> ~MBUSDF

so that, and the contrapositives of these statements, are a good thing to keep in mind.

Now take a look at (E), which tells us that compost that’s dark brown in color and emits a strong ammonia smell isn’t good garden compost. Well, we already know from above that

SAS —> ~GGC

And so since this compost emits a strong ammonia smell, it’s not good compost, and (E) follows from the above statements and is correct.

(A) is wrong because we aren’t told anything about a relationship between percentage organic matter and sufficient decomposition.

(B) tells us

~40-60% organic matter & ~dark brown in color —> Makes soil less fertile & worsens soil drainage

And we’re never told about compost making the soil worse, so that’s not something we can conclude.

(C) is wrong because it doesn’t tell us anything about the compost being dark brown in color.

(D) is wrong because we aren’t told anything about “completely” decomposed in the stimulus.

Hope this helps! Feel free to ask any other questions that you might have.

rswafra on August 19, 2022

I didn't diagram this because I wasn't seeing conditional trigger words, but can now see how they might work well for that. Can you give some tips on when to diagram as conditional even though there isn't always conditional language (outside of All in the first sentence)? Or am I missing conditional language?