Premise:
In 2005, Maltania's WFPI was 60 pounds more than Italy's WFPI.
In 2006, Maltania's WFPI was 75 pounds more than Italy's WFPI.
Conclusion:
Between 2005 and 2006, Maltania's WFPI increased.

Case 1:
In 2005, Italy's WFPI = 100, Maltania's WFPI = 100+60 = 160.
In 2006, Italy's WFPI = 10, Maltania's WFPI = 10+75 = 85.
In this case, Maltania's WFPI decreases from 160 to 85.

To support the conclusion that Maltania's WFPI increased, the correct answer will probably show that Case 1 is not possible.

C: Between 2005 and 2006, Italy's WFPI decreased by 10 pounds per acre.
Here, Case 1 is not possible, since in Case 1 Italy's WFPI decreases by 90 pounds per acre.

Case 2:
In 2005, Italy's WFPI = 100, Maltania's WFPI = 100+60 = 160.
In 2006, Italy's WFPI = 100-10 = 90, Maltania's WFPI = 90+75 = 165.
In this case, Maltania's WFPI increases from 160 to 165.

Case 3:
In 2005, Italy's WFPI = 20, Maltania's WFPI = 20+60 = 80.
In 2006, Italy's WFPI = 20-10 = 10, Maltania's WFPI = 10+75 = 85.
In this case, Maltania's WFPI increases from 80 to 85.

In both cases, Maltania's WFPI increases by 5 pounds per acre.
Thus, the information in C SUPPORTS the conclusion that Maltania's WFPI increased.

The correct answer is C.

GMATGuruNY wrote:Premise:
In 2005, Maltania's WFPI was 60 pounds more than Italy's WFPI.
In 2006, Maltania's WFPI was 75 pounds more than Italy's WFPI.
Conclusion:
Between 2005 and 2006, Maltania's WFPI increased.

Case 1:
In 2005, Italy's WFPI = 100, Maltania's WFPI = 100+60 = 160.
In 2006, Italy's WFPI = 10, Maltania's WFPI = 10+75 = 85.
In this case, Maltania's WFPI decreases from 160 to 85.

To support the conclusion that Maltania's WFPI increased, the correct answer will probably show that Case 1 is not possible.

C: Between 2005 and 2006, Italy's WFPI decreased by 10 pounds per acre.
Here, Case 1 is not possible, since in Case 1 Italy's WFPI decreases by 90 pounds per acre.

Case 2:
In 2005, Italy's WFPI = 100, Maltania's WFPI = 100+60 = 160.
In 2006, Italy's WFPI = 100-10 = 90, Maltania's WFPI = 90+75 = 165.
In this case, Maltania's WFPI increases from 160 to 165.

Case 3:
In 2005, Italy's WFPI = 20, Maltania's WFPI = 20+60 = 80.
In 2006, Italy's WFPI = 20-10 = 10, Maltania's WFPI = 10+75 = 85.
In this case, Maltania's WFPI increases from 80 to 85.

In both cases, Maltania's WFPI increases by 5 pounds per acre.
Thus, the information in C SUPPORTS the conclusion that Maltania's WFPI increased.

The correct answer is C.

Hi Mitch,

In Choice A, what does 'same rate' mean? How can I prove that A is wrong?

Thanks

Mo2men wrote:
Hi Mitch,

In Choice A, what does 'same rate' mean? How can I prove that A is wrong?

Thanks

WFPI = (total weight of harvested grain)/(total number of acres).

Premise:
In 2005, Maltanis's WFPI was 60 pounds per acre more than Italy's WFPI.
In 2006, Maltania's WFPI was 75 pounds per acre more than Italy's.
A:
Between 2005 and 2006, the number of acres of wheat planted in both Maltania and Italy increased at the same rate.

2005:
Total weight of harvested grain in Maltania = 1060, total weight of harvested grain in Italy = 1000.
Number of acres in Maltania = 1, number of acres in Italy = 1.
WFPI in Maltania = 1060/1 = 1060.
WFPI in Italy = 1000/1 = 1000.
Difference = 1060-1000 = 60.

2006;
Total weight of harvested grain in Maltania = 200, total weight of harvested grain in Italy = 50.
Number of acres in Maltania = 2, number of acres in Italy = 2.
WFPI in Maltania = 200/2 = 100.
WFPI in Italy = 50/2 = 25.
Difference = 100-25 = 75.

In the case above, the total number of acres in each country DOUBLES (from 1 acre to 2 acres), but the WFPI in Maltania DECREASES (from 1060 to 100).

Thus, A does NOT strengthen the conclusion that the WFPI in Maltania increased.
Eliminate A.