In the arid land along the Colorado river

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In the arid land along the Colorado river

by gmatpart2 » Fri Apr 05, 2013 10:49 pm
In the arid land along the Colorado River, use of the river's water is strictly controlled: farms along the river each have a limited allocation that they are allowed to use for irrigation. But the trees that grow in narrow strips along the river's banks also use its water. Clearly, therefore, if farmers were to remove those trees, more water would be available for crop irrigation
Which of the following, if true, most seriously weakens the argument?


a. The trees along the river's banks shelter it from the sun and wind, thereby greatly reducing the amount of water lost through evaporation
b. Owners of farms along the river will probably not undertake the expense of cutting down trees along the banks unless they are granted a greater allocation of water in return
c. Many of the tree species currently found along the river's banks are specifically adapted to growing in places where tree roots remain constantly wet.
d. The strip of land where trees grow along the river's banks would not be suitable for growing crops if the trees were removed.
e. The distribution of water allocations for irrigation is intended to prevent farms father upstream from using water needed by farms father downstream.

OA is "A". What if the trees use more water than they save from being evaporated? In this case A would in fact strengthen the argument. Also, I see no real merit in any other option.

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by GMATGuruNY » Sat Apr 06, 2013 3:36 am
gmatpart2 wrote:In the arid land along the Colorado River, use of the river's water is strictly controlled: farms along the river each have a limited allocation that they are allowed to use for irrigation. But the trees that grow in narrow strips along the river's banks also use its water. Clearly, therefore, if farmers were to remove those trees, more water would be available for crop irrigation
Which of the following, if true, most seriously weakens the argument?


a. The trees along the river's banks shelter it from the sun and wind, thereby greatly reducing the amount of water lost through evaporation
b. Owners of farms along the river will probably not undertake the expense of cutting down trees along the banks unless they are granted a greater allocation of water in return
c. Many of the tree species currently found along the river's banks are specifically adapted to growing in places where tree roots remain constantly wet.
d. The strip of land where trees grow along the river's banks would not be suitable for growing crops if the trees were removed.
e. The distribution of water allocations for irrigation is intended to prevent farms father upstream from using water needed by farms father downstream.

OA is "A". What if the trees use more water than they save from being evaporated? In this case A would in fact strengthen the argument. Also, I see no real merit in any other option.
This is a PLANNING argument.
The plan is to REMOVE THE TREES.
The conclusion is that MORE WATER will be available for crop irrigation.
The assumption is that there is NO PROBLEM WITH THE PLAN.
To weaken the conclusion, the correct answer will show that there IS a problem with the plan: that removing the trees will NOT make more water available for crop irrigation.
Answer choice A: The trees along the river's banks shelter it from the sun and wind, thereby greatly reducing the amount of water lost through evaporation.
If the trees GREATLY REDUCE THE AMOUNT OF WATER LOST through evaporation, removing the trees is likely to make LESS water available for crop irrigation, weakening the conclusion that there will be MORE water available.

The correct answer is A.

Do not play the "what if" game; do not make up a complicated story to justify or eliminate an answer choice.
The OA here is correct because it clearly attacks the link between FEWER TREES and MORE WATER.
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by aditya8062 » Sat Apr 06, 2013 5:15 am
good day Mitch
plz tell me what make D a bad choice
thanks and regards

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by psr3458 » Sat Apr 06, 2013 10:57 pm
The conclusion here is, "if farmers were to remove those trees, more water would be available for crop irrigation"

The issue here is about the amount of water that would be available for crop irrigation, not whether that strip of land would be suitable or not.

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by insanejuxtapose » Tue Apr 09, 2013 1:21 am
GMATGuruNY wrote:
gmatpart2 wrote:In the arid land along the Colorado River, use of the river's water is strictly controlled: farms along the river each have a limited allocation that they are allowed to use for irrigation. But the trees that grow in narrow strips along the river's banks also use its water. Clearly, therefore, if farmers were to remove those trees, more water would be available for crop irrigation
Which of the following, if true, most seriously weakens the argument?


a. The trees along the river's banks shelter it from the sun and wind, thereby greatly reducing the amount of water lost through evaporation
b. Owners of farms along the river will probably not undertake the expense of cutting down trees along the banks unless they are granted a greater allocation of water in return
c. Many of the tree species currently found along the river's banks are specifically adapted to growing in places where tree roots remain constantly wet.
d. The strip of land where trees grow along the river's banks would not be suitable for growing crops if the trees were removed.
e. The distribution of water allocations for irrigation is intended to prevent farms father upstream from using water needed by farms father downstream.

OA is "A". What if the trees use more water than they save from being evaporated? In this case A would in fact strengthen the argument. Also, I see no real merit in any other option.
This is a PLANNING argument.
The plan is to REMOVE THE TREES.
The conclusion is that MORE WATER will be available for crop irrigation.
The assumption is that there is NO PROBLEM WITH THE PLAN.
To weaken the conclusion, the correct answer will show that there IS a problem with the plan: that removing the trees will NOT make more water available for crop irrigation.
Answer choice A: The trees along the river's banks shelter it from the sun and wind, thereby greatly reducing the amount of water lost through evaporation.
If the trees GREATLY REDUCE THE AMOUNT OF WATER LOST through evaporation, removing the trees is likely to make LESS water available for crop irrigation, weakening the conclusion that there will be MORE water available.

The correct answer is A.

Do not play the "what if" game; do not make up a complicated story to justify or eliminate an answer choice.
The OA here is correct because it clearly attacks the link between FEWER TREES and MORE WATER.
Question for Mitch. Why cant it be B? I thought we are trying to weaken the argument and not just the conclusion.

The argument says that the farms are allocated limited water for irrigation and that more water would be available for irrigation if they cut the trees.

B says that even if they cut the trees, if farms are not alloted more water for irrigation, then there is no incentive for the owners to cut the trees even if more water would be available.

Mitch could you please throw some light on this?

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by GMATGuruNY » Wed Apr 10, 2013 8:21 am
insanejuxtapose wrote:
Question for Mitch. Why cant it be B? I thought we are trying to weaken the argument and not just the conclusion.

The argument says that the farms are allocated limited water for irrigation and that more water would be available for irrigation if they cut the trees.

B says that even if they cut the trees, if farms are not alloted more water for irrigation, then there is no incentive for the owners to cut the trees even if more water would be available.

Mitch could you please throw some light on this?
The argument concludes that more water would be available for irrigation IF FARMERS WERE TO REMOVE THOSE TREES that grow in narrow strips along the river's banks.
Whether farmers can or will remove the trees is irrelevant.
Our only concern is what will or will not happen IF THE TREES ARE IN FACT REMOVED.

In general, when a CR asks us to WEAKEN A PLAN:
We should be skeptical of answer choices suggesting that the plan might be difficult to implement.
Whether the plan can be implemented is usually not the issue.
Rather, our concern is whether the plan -- IF IMPLEMENTED -- will achieve the desired result.
Typically, the correct answer choice will offer a reason that the plan will NOT achieve the desired result.
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by RBBmba@2014 » Mon Sep 28, 2015 10:42 pm
Hi Mitch - a quick question on Option D.

I think, Option D is wrong because :

1. It doesn't DIRECTLY mention anything what would be the effect of availability of water for crop irrigation if trees are removed!

2. It talks about how removing trees would make it difficult to carry out crop irrigation IN the (narrow) strip of land where trees grow along the river's banks. BUT we're NOT really bothered about those (narrow) strip of land to continue crop irrigation, I mean who cares if those portion (re narrow strip) of land is NOT available for irrigation as we'll still have the majority of river banks (AT LEAST muhc more than this narrow strip) available for crop irrigation.

So, Option D doesn't WEAKEN the CONCLUSION that says removing trees means more water available for crop irrigation.

Is this INTERPRETATION right ?
GMATGuruNY wrote: In general, when a CR asks us to WEAKEN A PLAN:
We should be skeptical of answer choices suggesting that the plan might be difficult to implement.
Whether the plan can be implemented is usually not the issue.
Considering EXCEPTIONS, for WEAKEN A PLAN Qs do we have any OFFICIAL instances in which the OA revolves around the above line -- whether the plan might be difficult to implement or so ? OR is it(re such line of reasoning) ALWAYS avoided on GMAT ?

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by RBBmba@2014 » Mon Jan 18, 2016 10:25 am
Hi GMATGuruNY - could you please share your feedback on my above concerns Sir ?

Look forward to know your thoughts. Much thanks in advance!

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by RBBmba@2014 » Mon Jan 25, 2016 6:34 am
RBBmba@2014 wrote: I think, Option D is wrong because :

1. It doesn't DIRECTLY mention anything what would be the effect of availability of water for crop irrigation if trees are removed!

2. It talks about how removing trees would make it difficult to carry out crop irrigation IN the (narrow) strip of land where trees grow along the river's banks. BUT we're NOT really bothered about those (narrow) strip of land to continue crop irrigation, I mean who cares if those portion (re narrow strip) of land is NOT available for irrigation as we'll still have the majority of river banks (AT LEAST muhc more than this narrow strip) available for crop irrigation.

So, Option D doesn't WEAKEN the CONCLUSION that says removing trees means more water available for crop irrigation.

Are my above INTERPRETATIONS correct ?
Hi Verbal Experts (Ceilidh/Dave/Mitch/others) - could you please share your thoughts on my above concerns ?

Look forward to know your explanations. Much thanks for your cooperation!
GMATGuruNY wrote: In general, when a CR asks us to WEAKEN A PLAN:
We should be skeptical of answer choices suggesting that the plan might be difficult to implement.
Whether the plan can be implemented is usually not the issue.
@ Mitch/Other Verbal Experts -- Considering EXCEPTIONS, for WEAKEN A PLAN Qs do we have any OFFICIAL instances in which the OA revolves around the above line -- whether the plan might be difficult to implement or so ? OR is such line of reasoning ALWAYS avoided on GMAT ?

Any thoughts on the above ?

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by RBBmba@2014 » Mon Sep 25, 2017 5:06 am
Considering EXCEPTIONS, for WEAKEN A PLAN Qs do we have any OFFICIAL instances in which the OA revolves around the above line -- whether the plan might be difficult to implement or so ? OR is such line of reasoning ALWAYS avoided on GMAT ?
Hi Verbal Experts,
Could you please quickly share your thoughts on my above mentioned concerns ?
Much thanks in advance!