The trees always blossom in May if April rainfall exceeds 5 centimeter

Question

The trees always blossom in May if April rainfall exceeds 5 centimeters. If April rainfall exceeds 5 centimeters, then the reservoirs are always full on May 1. The reservoirs were not full this May 1 and thus the trees will not blossom this May.

Which one of the following exhibits a flawed pattern of reasoning most similar to the flawed pattern of reasoning in the argument above?

(A) If the garlic is in the pantry, then it is still fresh. And the potatoes are on the basement stairs if the garlic is in the pantry. The potatoes are not on the basement stairs, so the garlic is not still fresh.

(B) The jar reaches optimal temperature if it is held over the burner for 2 minutes. The contents of the jar liquefy immediately if the jar is at optimal temperature. The jar was held over the burner for 2 minutes, so the contents of the jar must have liquefied immediately.

(C) A book is classified “special” if it is more than 200 years old. If a book was set with wooden type, then it is more than 200 years old. This book is not classified “special,” so it is not printed with wooden type.

(D) The mower will operate only if the engine is not flooded. The engine is flooded if the foot pedal is depressed. The foot pedal is not depressed, so the mower will operate.

(E) If the kiln is too hot, then the plates will crack. If the plates crack, then the artisan must redo the order. The artisan need not redo the order. Thus, the kiln was not too hot.

prateekchugh · Accepted Answer

KAPLAN OFFICIAL EXPLANATION

(A) Parallel Reasoning (Logical Flaw)

When a Parallel Reasoning argument contains Formal Logic, translating the stimulus algebraically will make it much easier to compare to the answer choices. Translating the first two sentences of the stimulus, we learn that one trigger (April rainfall in excess of 5 centimeters—we’ll call this “X”) causes two necessary results: the trees will blossom in May (we’ll call this “Y”), and the reservoirs will be full on May 1 (we’ll call this “Z”). So in our formal logic notation, we can write “If X → Y” and “If X → Z.” Our last sentence tells us that since our reservoirs aren’t full (in other words, “no Z”), the trees will not blossom (in other words, “no Y”).

So our final formal logic statement would be “No Z, so no Y.” The absence of one result does not guarantee the absence of the other, so here is the flaw that we’re looking for in the answer choices. Armed with our algebraic notation, we can more easily find a match.

(A)  The first two sentences of  (A)  give us two necessary results following from the same trigger— just like the stimulus. Let “garlic in the pantry” equal “X,” “garlic still fresh” equal “Y,” and “potatoes on the basement stairs” equal “Z.” Then we have “If X → Y” and “If X → Z.” Our last sentence says that the potatoes are not on the stairs (“no Z”), so the garlic isn’t fresh (“no Y”). Perfect match. We don’t even have to read any other answer choices because we just matched the entire stimulus point by point.

For the record:

(B)  actually connects statements correctly. Connecting the first two sentences, we learn that if the jar is held over the burner for more than 2 minutes (“X”), it will reach optimal temperature (“Y”), which will in turn cause its contents to liquefy (“Z”). The conclusion of  (B)  makes a sound deduction based on the connection of these statements. In our algebraic notation, this argument would have read as follows: “If X → Y; if Y → Z; X occurred, so Z occurred.” This is correct reasoning. Eliminate.

(C)  Again, let’s do some algebraic substitution. We’ll let “book set with wooden type” equal “X,” “book more than 200 years old” equal “Y,” and “book classified as special” equal “Z.” In that case, the argument reads: “If Y → Z; if X → Y; no Z, so no X.” If we contrapose the initial statements in this argument, we’ll see that it uses correct reasoning also. Eliminate.

(D)  Abstracting the terms of this argument gives us “If X → no Y” (mower operating = “X” and engine flooded = “Y”), then “If Z → Y” (foot pedal depressed = “Z”). But the conclusion becomes “no Z, so X.” We can’t contrapose any statement to find out what happens if there’s “no Z,” so the logic is certainly flawed here. It just isn’t flawed in the same way as that of the stimulus. Eliminate.

(E)  follows exactly the same logically sound structure as  (C) , just in a slightly different order: “If X → Y; if Y → Z; no Z, so no X.” Eliminate.

mSKR · Answer

If A then B
If A then C
If not C and thus –B

In Short , If A then B , If A then C . But No C no B

If a then B
If A then C
If no C then no B
 CORRECT

If A then B
If C then D
If E then C

If A then B
If C then A
If –B then –C

If A then B
If C then –B
If B then A

If A then B
If B then C
If –C then -A

Bambi2021 · Answer

One sufficient condition leads to two necessary conditions. The flaw is that if one of the necessary conditions have not occurred, the other necessary condition wont occur. This is what we find in A.

Thekingmaker · Answer

At last with the current weakly ranking dropping me to the lowest possible tier it feels so marvelous yeah Why did i chose A because when we analayse the final the thing doesn't end positively just like our life which made me narrow down to A and E , e had 2 criteria to be satisfied because of which i eleminated the argument given to us had only one freaking condition just the filling of the reservouir , therefore with only the filling of potatoes in the basement i narrowed down to A

ds2112 · Answer

I got confused with D and A, is it not the same as X then Y, no Y no X

egmat · Answer

Hi ds2112,

Good instinct to formalize, but the pattern here isn't the clean "X → Y, no Y, so no X." That would actually be a  valid  contrapositive. The stimulus is doing something sneakier, and once you see its signature, A locks in and D falls away.

The signature of the stimulus

Notice both "if" statements start from the  same trigger :

- April rain >  5  cm → trees blossom ( A → B )
- April rain >  5  cm → reservoirs full ( A → C )
- reservoirs  not  full → trees  won't  blossom ( ¬C ⟹ ¬B )

So it's  one trigger, two separate results , and it wrongly assumes that if one result (C) is missing, the other result (B) must be missing too. That's the flaw.

Why A matches

- garlic in pantry → fresh ( A → B )
- garlic in pantry → potatoes on stairs ( A → C )
- potatoes  not  on stairs → garlic  not  fresh ( ¬C ⟹ ¬B )

Same trigger feeding two results, same wrong leap. Exact match.

Why D is different

D's two conditionals do  not  share one trigger, and they point in opposite directions:

- mower operates → engine not flooded ( M → ¬F )
- pedal depressed → engine flooded ( P → F )
- pedal  not  depressed → mower operates ( ¬P ⟹ M )

Here the conclusion negates the antecedent of the  second  rule (¬P) to reach M. There's no shared starting trigger and no "two results" setup - so even though D is also flawed, it's a  different  flaw.

The quick test

Ask:  do both "if" statements begin from the same condition?

- In the stimulus and A -  yes  (rain; garlic in pantry).
- In D -  no  (one starts with the mower, the other with the pedal).

That single check separates A from D every time.

Answer: A

guddo · Answer

The trees always blossom in May if April rainfall exceeds 5 centimeters. If April rainfall exceeds 5 centimeters, then the reservoirs are always full on May 1. The reservoirs were not full this May 1 and thus the trees will not blossom this May.
 
 Which one of the following exhibits a flawed pattern of reasoning most similar to the flawed pattern of reasoning in the argument above?

The argument says that April rainfall above 5 cm would cause two things: trees blossom and reservoirs are full. Since the reservoirs were not full, we know only that April rainfall did not exceed 5 cm.  The flaw  is assuming that rainfall above 5 cm is the  only  way the trees can blossom.

(A) If the garlic is in the pantry, then it is still fresh. And the potatoes are on the basement stairs if the garlic is in the pantry. The potatoes are not on the basement stairs, so the garlic is not still fresh.

This is correct.   Same pattern: garlic in pantry would cause two things: garlic fresh and potatoes on stairs. Since the potatoes are not on the stairs, we know only that the garlic is not in the pantry. We do not know that the garlic is not fresh.

(B) The jar reaches optimal temperature if it is held over the burner for 2 minutes. The contents of the jar liquefy immediately if the jar is at optimal temperature. The jar was held over the burner for 2 minutes, so the contents of the jar must have liquefied immediately.

This is valid. Holding the jar over the burner leads to optimal temperature, and optimal temperature leads to liquefaction.

(C) A book is classified “special” if it is more than 200 years old. If a book was set with wooden type, then it is more than 200 years old. This book is not classified “special,” so it is not printed with wooden type.

This is valid. If wooden type leads to more than 200 years old, and more than 200 years old leads to “special,” then not special rules out wooden type.

(D) The mower will operate only if the engine is not flooded. The engine is flooded if the foot pedal is depressed. The foot pedal is not depressed, so the mower will operate.

This is flawed, but not in the same way. It wrongly concludes that the mower will operate from the fact that the foot pedal is not depressed.

(E) If the kiln is too hot, then the plates will crack. If the plates crack, then the artisan must redo the order. The artisan need not redo the order. Thus, the kiln was not too hot.

This is valid. If too hot leads to cracked plates, and cracked plates lead to redoing the order, then no need to redo the order rules out the kiln being too hot.

Answer: (A)

The trees always blossom in May if April rainfall exceeds 5 centimeter

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Critical Reasoning (CR) Questions

The trees always blossom in May if April rainfall exceeds 5 centimeter

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards