Question: Wheat Production

Comment on Wheat Production

I don't really agree with this. Isn't it possible that Italys productivity decreased while Maltanias remained the same? Italys decrease has nothing to do with a possible increase of Maltania
gmat-admin's picture

The passage tells us that, from 2005 to 2006, Maltania's WFPI ADVANTAGE over Italy's WFPI increased by 15 pounds per acre.

Answer choice C tells us that from 2005 and 2006 Italy's WFPI decreased by 10 pounds per acre. So, in order for Maltania's WFPI ADVANTAGE over Italy's WFPI to increase by 15 pounds per acre, it MUST be the case that Maltania's WFPI increased by 5 pounds per acre from 2005 to 2006.
Does that help?
If you're not convinced, please provide some figures that meet the given information, yet demonstrate that Maltania's WFPI did not increase from 2005 to 2006.

For B and E you say that there are plenty assumptions that need to be made before accepting them as the answer choices but don't list some of the possible assumptions. For B, if there was more sunshine in Maltania wouldn't that contribute to more wheat?
gmat-admin's picture

More sunshine in Maltania COULD contribute to more wheat. However, we aren't told anything about Italy's sunshine. So, one of the assumptions for this answer choice is that Italy's growing conditions remained the same (or worsened) while Maltania's growing conditions improved.

Another assumption is that 20% more sunshine actually improves WFPI. More sunshine suggests less rain, which might make matters worse.

I think it's a tricky and subtle question and Brent elaboration make it clear for me that only answer C is correct.
Thank you Brent

Can you please explain why not A? Does i not say that if the number of acres increased at same rate and still the productivity of MAltania was now more by 15%? The answer C, i feel, could also lead to the fact that the decrease in Italy's prodcutivity could be the reason for the difference of 15%
gmat-admin's picture

The WFPI measures the average productivity PER ACRE of land. So, the NUMBER of acres has no effect on the WFPI.

Very tricky!

Great explanations!

Hello Sir,
Regarding C if say
Italy's WFPI in 2005 = 3000
=> Maltania's WFPI in 2005= 3060
From the choice C we have,
Italy's WFPI in 2006 = 3000 - 300 = 2700
=> Maltania's WFPI in 2006= 2775 (<3060) which suggests a decrease.
I rejected C on these grounds since I need to know if Italy's WFPI is greater than or less than 1350 to judge if this option strengthens or weakens the argument. In absence of that info I had to go with B
gmat-admin's picture

Wow, I read the original argument several times and couldn't find the flaw in your counterexample! In fact, I was very close to concluding that the question is faulty and removing it!!

Then, I found the problem: In your scenario, Italy's WFPI decreases by 10 PERCENT (from 3000 pounds to 2700 pounds). However, answer choice C actually tells us that Italy's WFPI decreases by 10 POUNDS.

I strike again! Quite sure I can get at least 30 40 points extra if I stop doing stuff like this :(. Thanks sir
gmat-admin's picture

Glad to help! It was a good mental exercise for me!!

This is very tricky question? what is difficult level 750+?
gmat-admin's picture

I'd place the difficulty level somewhere in the 700-800 range.

Mltania's productivity index can only increase when Italy's present value is greater than 60/72 according to the premises. Since 10-1/10 is greater than 60/72, answer choice C is correct. But the problem is, is this tested often on GMAT? I donnot want to solve math problems in CR section.
gmat-admin's picture

This is definitely a "mathy" Critical Reasoning question. There are SOME Critical Reasoning questions that require some mathematical reasoning, but they're somewhat rare.

Here's another mathy CR question from the Official Guide: http://www.beatthegmat.com/experts-please-reply-t76489.html

aren't C and D almost same?
gmat-admin's picture

While C and D both SUGGEST that Italy's wheat production decreased in 2006, only answer choice C explicitly says so.

While a drought COULD cause a decrease in wheat production, this need not be the case. Keep in mind that a drought typically means an increase in sunshine. So, if Italy's wheat farms had adequate irrigation in 2006, it's actually possible that its WFPI could have increased that year.

Does that help?

Cheers,
Brent

thanks a lot Brent. Yes that helps

Hi Brent!

Could you explain why Option A is incorrect?
Option A talks about the number of acres of wheat planted in Maltania and Italy increasing at the same rate.

If the number of acres of wheat planted increases, the average number of pounds harvested increases and as a result the WFPI increases (since the numerator increases)

Could you please let me know why my logic is flawed?

Thanks
gmat-admin's picture

Keep in mind that the WFPI is based on TWO factors:
1) Number of pounds of grain harvested
2) Number of acres of grain

Your solution considers only one of those factors.

Consider this possible scenario:
In 2005,
- Italy harvested 100 pounds of grain from 10 acres (WFPI = 100/10 = 10)
- Maltania harvested 700 pounds of grain from 10 acres (WFPI = 700/10 = 70)
So, in 2005, Maltania's WFPI was 60 pounds per acre greater than Italy's

In 2006,
- Italy harvested 100 pounds of grain from 10 acres (WFPI = 100/10 = 10)
- Maltanie harvested 1700 pounds of grain from 20 acres (WFPI = 1700/20 = 85)
So, in 2006, Maltania's WFPI was 75 pounds per acre greater than Italy's

From 2005 to 2006, Italy created ZERO more acres of grain fields.
However, from 2005 to 2006, Maltania created TEN more acres of grain fields.

So, answer choice A does not hold true.

Does that help?

Cheers,
Brent

Hi Brent!
I'm afraid I'm still unable to fully grasp the solution.
My understanding thus far is that Maltania now has created 10 more acres of grain fields.
Maltania's WFPI has shifted from a 70 in 2005 to an 85 in 2006. That's an increase right?
So, its wheat field productivity should have increased?

Thank you in advance for your patience and for clarifying!
gmat-admin's picture

According to my example, between 2005 and 2006, Maltania created 10 additional acres of grain fields. During that same time, Italy created ZERO additional acres of grain fields.

So, we can eliminate answer choice A, since it says both countries added the same number of acres of grain fields.

Your question: "So, its wheat field productivity should have increased?"

Yes, Maltania's productivity INDEX (WFPI) definitely increased from 70 to 85. However, there is more than one way in which the WFPI can increase.

For example, the number of pounds of grain harvested increased or the number of acres of grain decreased, or some combination of these.

Consider this possible scenario:
In 2005, Maltania harvested 700 pounds of grain from 10 acres (WFPI = 700/10 = 70)
In 2006, Maltania harvested 85 pounds of grain from 1 acres (WFPI = 85/1 = 85)
We can see that, although the WFPI increased, the wheat harvest actually decreased.

Does that help?

Cheers,
Brent

Hi Brent,

Just for the sake of mental exercise,

If the conclusion was: "Therefore, Maltania's wheat field productivity must have remained steady during that period."

then the answer choice C, in order to make it a correct option, should be modified as follows:

Between 2005 and 2006, Italy's wheat field productivity decreased by 15 pounds per acre, then Maltania's

Am I right?

Thank you in advance,
gmat-admin's picture

That's correct. Nice work.

Very tricky question. My 1st assumption was that Italy didn't regress because if their productivity had regressed then we couldn't consider Maltania's productivity as an improvement... So C was the opposite of the argument's assumption. A was my answer but I read the comments and understood why you eliminated it. However, I don't get the flaw in my assumption. How can we consider that Maltania's production increased if in fact Italy's production decreased? Is it because 60+10 should give 70 lb difference in 2006 and not 75? So they increased their productivity (+5) between 2005 and 2006? Thanks
gmat-admin's picture

Let's add a little bit of math to better understand the solution
Let X = Italy's WFPI in 2005
So, X + 60 = Maltania's WFPI in 2005 (since we're told its WFPI was 60 pounds per acre greater than Italy's)

Answer Choice C tells us that, in 2006, Italy's WFPI decreased 10 pounds per acre.
This means (X - 10) = Italy's WFPI in 2006
The passage tells us that, in 2006, Maltania's WFPI was 75 pounds per acre greater than Italy's
In other words, (X - 10) + 75 = Maltania's WFPI in 2006
When we simplify this we get: (X + 65) = Maltania's WFPI in 2006

So,
(X + 60) = Maltania's WFPI in 2005
(X + 65) = Maltania's WFPI in 2006
So, from 2005 to 2006, Maltania's WFPI increased by 5 pounds per acre

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