A ten-year comparison between Brazilian and Canadian crops

Question

A ten-year comparison between Brazilian and Canadian crops showed that Brazilian yields are 68% of Canadian yields when compared on the basis of per planted acre. However, Brazilian yields are 115% of Canadian yields when measured per agricultural acre.

Based on this information, which of the following can most reliably be inferred about Brazilian and Canadian agriculture over this time period?

A. A greater percentage of Canadian agricultural acreage was unplanted than of Brazilian agricultural acreage.

B. A majority of Canadian acreage is unplanted.

C. More total acres were unplanted in Canada than in Brazil.

D. Brazil had more acres planted than unplanted while Canada has more acres unplanted than planted.

E. Brazil produced more total crops than Canada.

IanStewart · Accepted Answer

It's a confusingly worded question, but it tests something many CR questions test: do you confuse ratios/percentages with actual numbers. You can rule out C and E instantly, since the stem only talks about ratios, and C and E talk about actual numbers. You can also rule out D without even reading the stem, since if D is true, then A would also need to be true (D is a special case of A). There cannot be 2 correct answers to a GMAT question, so D cannot be right. So if you can see that B is not a valid inference, you can be sure A is right.

But we can see why A is correct. The key distinction in the question is between "planted acres" and "agricultural acres". I think we're meant to interpret "planted acres" as land used specifically for crops, and "agricultural acres" as all land available - some of that land will be used for crops, but some might be used for grazing cattle or some other purpose.

The stem tells us that "Brazilian yields are 68% of Canadian yields per planted acre." That means: for each acre they use for planting, Canada gets more crops. So if Brazil and Canada were each planting on an exactly equal proportion of their agricultural land, Canada would get a higher yield per acre, because they're more efficient at farming. But we learn in the second sentence that is not the case. When you look at all land, planted or not, Brazil gets a higher yield per acre. So Brazil must be planting on more of its land than Canada is to compensate for their lower efficiency per acre planted. That's what A says.

GyanOne · Answer

The answer is (A).

Lets set up the answer first, before we evaluate the possible answer choices. Yield is the amount of crop grown on a piece of land. When compared on a per planted acre basis, crops in Brazil have much lower yield (68%) when compared by crops in Canada. However, when compared on a per agricultural acre basis, Brazilian crops have a higher (115%) yield than Canadian crops.

Now lets evaluate the answer choices.

(A): CORRECT. If Brazilian crops have a lower planted yield than Canadian crops, then the only way for Brazilian crops to have a greater agricultural yield is if a greater portion of every agricultural acre is planted in Brazil than it is in Canada. Imagine this: if both Brazilian crops and Canadian crops had the same planted yield, and Brazil had a greater agricultural yield, we would conclude that this must be because a greater proportion of every acre is planted in Brazil than in Canada. Since the Brazilian planted yield is less than the Canadian yield, this must certainly be true. 
(B): This is the wrong inference. It is possible that a majority of acreage in Canada is planted - the only truth, as we saw, is that on a per agricultural acre basis, Canada has a lesser percentage of its acreage planted than Brazil does. It is possible that Canada has 80% of its acreage planted while Brazil has 95% of its acreage planted. Would you call 80% less than a majority? No. 
(C): This cannot be inferred. The question discusses yields on a per agricultural acre basis. There is no mention of the total acres of unplanted acreage in Canada or Brazil. It is possible that Canada has a greater number of total planted acres than Brazil does - only they are more sparsely planted than the Brazilian ones. Incorrect. 
(D): This is the wrong inference following the logic in option (C) above. Incorrect. 
(E): This cannot be inferred - it is possible that Canada produced more crops, even if by using its land less efficiently. Incorrect.

mehulsayani · Answer

Thanks a lot for ur explanation

But, how did u figure out that D was a special case of A? I was confused between A and D only, but marked D, but both seemed the same to me.

IanStewart · Answer

D says "more than half of the acres in Brazil are planted, while less than half of the acres in Canada are planted". If that's true, then certainly a higher % of acres are planted in Brazil than in Canada, which is what A says. So if D is a correct answer to this question, then A would also need to be a correct answer, and since questions can't have 2 correct answers, logically D just cannot be right.

grumpytesttaker · Answer

If you draw a diagram for this as you are reading the stimulus, it's a lot easier to see what's going on without getting entangled in the per planted, per agricultural acreage mumbo jumbo.

Draw two big boxes representing Brazil and Canada's agricultural acreage (agricultural acreage is bound to be bigger than planted acreage). Inside the Brazil box, draw five smaller boxes representing planted acres and write 68 (representing crops yielded) on each of them. Similarly, draw three smaller boxes inside Canada's big box and write 100 (crops yielded) on each. this is what the stimulus is saying. that per planted acre, brazil yields only 68% of canada's per planted yield. but in terms of the bigger box or agricultural acreage, brazil yields more than canada. so what is the question saying? there is just more planted acres in brazil than in canada. if u look at per planted acre, u see that canada yields more, but if u look at the total crops produced, brazil wins by virtue of it having more planted acres.

Armed with this understanding, you can attack the choices.

A. this is in line with our understanding. definitely a contender if not THE answer.
B. a majority of canadian.... majority? this is not descriptive enough. FAIL.
C. more total acres were unplanted in Can than Bra. close but total acres? it's trying to be tricky. we are talking about planted and agricultural acres and now total acres just brings the whole of the land mass into picture. Vague, beyond, irrelevant, whatever. FAIL.
D. Sounds reasonable but the second part of this choice- canada has more unplanted than planted- is saying too much and also it says "acres" doesn't specify agricultural or planted. FAIL.
E. This sounds reasonable but the stimulus talks in terms of percentage- that brazil yields 68% less per PA but 115% more per AA. but the numbers that form the base for those percentages are unclear. this becomes that data sufficiency question where both statement 1 and 2 are together insufficient. 
Hence A.
Hope this helps.

SUK123 · Answer

Very good job guys!!!

I just want to know what's your reason to dismiss D as an option.

hubahuba · Answer

Same question here. How did we reason out option D? Even though I got the answer right, D slowed me down significantly. I was stuck on this for over 280 seconds!

Here's my reasoning for this one:
B = 0.68% C (in terms of planted acre)
B = 1.15% C (in terms of agricultural acre)

So it must be that B's yield is lower (lower yield per planted acre), but also that B must be planting/cultivating more land since it's producing more than C (higher output than C). With this information, I deduce that A must be true --> "A greater percentage of Canadian agricultural acreage was unplanted than of Brazilian agricultural acreage."

Now, what about D --> "Brazil had more acres planted than unplanted while Canada has more acres unplanted than planted."

In other words, Brazil's %Planted (Planted / Unplanted) is greater than Canada's % Planted --> Given B = 1.15% C. 
Doesn't second part of the argument confirm this? Can someone help explain why my reasoning is flawed? much appreciated...

Thanks.

Udai · Answer

B(planted)=.68C(Planted)
B(Agr)=1.15C(Agr)
for these variables the yield is constant ,only factor that changes is the number of acres for ex: B(planted) = Total Yeild/Number of Planted acres so for B(planted) value to increase then Number of planted acres must decrease . This means

If C(Planted)>B planted & C(Agr)< B(Agr) means the Agr area in canada must have increased at a higher proportion than Agr area in Brazil

I got the and wrong btw …

TehMoUsE · Answer

If you are unsure on these type of number questions, here is a good guessing tip

(got it from PowerBible CR) 1, If questions only states percentage in the stimulus ----> Choose answer with percentage 2, If questions only states numbers in the stimulus ----> Choose answer with numbers If we use the guessing strategy on this particular question, we choose A and get a correct answer 8-)

manishtank1988 · Answer

my 2 cents:
per planted acre - B = 0.68*C
i.e. (all the yield produced in B)/(all the PLANTED AGRICULTURAL land in B) &
(all the yield produced in C)/(all the PLANTED AGRICULTURAL land in C)

whereas

per agricultural acre - B = 1.15*C
i.e. (all the yield produced in B)/(all the PLANTED + UNPLANTED AGRICULTURAL land in B) &
(all the yield produced in C)/(all the PLANTED + UNPLANTED AGRICULTURAL land in C)

Thus what A is saying is that - there is a greater portion of unplanted agricultural land in C than in B
and D ( which is what i selected and got wrong!!! ) means -
D - B has => planted acre > unplanted acre and C has planted acre < unplanted acre
Well there is no way to say this is true with certainty and in inference questions we NEED answer to/must be TRUE!!!

750Barrier · Answer

just as we do in data sufficiency questions, you can negate or create a scenario in which D gives 2 results.

For example - you may think that perhaps brazil had equal distribution between tow types of land, and Canada has extremely low in one and high in another. you will get there . Hope it helps !

san10789 · Answer

B=Brazil C=Canada Given , B < C (/plantation acre) by this logic B < C (/agriculture acre) but given B > C (/agriculture acre) Therefore, C > B (/unplanted area) Same as choice A.

shubhim20 · Answer

KarishmaB   Bunuel  please explain this question can't choose which one would be right choice

A ten-year comparison between Brazilian and Canadian crops

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A ten-year comparison between Brazilian and Canadian crops

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