In the past the country of Siduria has relied heavily on

A. In Siduria the rate of fuel consumption is rising no more quickly than the rate of fuel production. - Some day in near future, the gap between consumption and production of fuel will be zero and the necessity of oil import will not be necessary for Siduria. - Correct
B. Domestic production of natural gas is rising faster than is domestic production of oil in Siduria. - If this is the case, it still wont be enough to explain the usage of oil in near future and how the country would cope with it - Incorrect
C. No fuel other than natural gas is expected to be used as a replacement for oil in Siduria. - Out of scope - Incorrect
D. Buildings cannot be heated by solar energy rather than by oil or natural gas. - Out of scope - Incorrect
E. All new homes that are being built will have natural-gas-burning heating systems. - If we only talk about new homes, what about the old home that still use oil for heating purposes. Does not give correct idea on the consumption pattern - Incorrect

Hey guys,

Can you help me understand why C is not correct?

To me, the statement seems to conclude that because demand of natural gas (which can be produced in Siduria) is increasing, export of oil (which is mainly from export) will decline.

Conclusion: Reliance on foreign sources for Siduria will decline
Premise: Siduria's demand in natural gas is increasing
Premise: Siduria makes a lot of natural gas

If, for example, the demand of alternative energy, such as bioenergy that might not be able to be produced in Siduria, significantly increases in Siduria, then Siduria will not lower its reliance of foreign source. To me, C is also a pretty solid assumption the author has. I totally agree A is also assumed, but author seems to assume C as well.

Hi Cssmarimo

I liked that you've clearly stated the conclusion & premises. You've also tried to apply negation which is an important tool for assumption question. However, I somehow feel that you should give this argument a second read. There are some points which you seem to have missed. I'm sure a re-read would surely help!



We know that the production of natural gas each year exceeds its demand. I couldn't understand how you've related demand of natural gas with export of oil. Could you please elaborate on this? The argument looks for an option that supports the conclusion that Siduria's reliance on foreign sources for fuel will decline, which means Siduria's import of fuel would decline.



You seem to have missed the conditional structure of the conclusion and that might have led to the fundamental gap in your understanding of this question.

Conclusion: Note the conclusion presents a condition. If X, then Y.
If these trends in fuel production and usage continue, therefore, Sidurian reliance on foreign sources for fuel should decline soon.


Premises:
1) Implementation of a program to convert heating systems from oil to natural gas.
2) Production of natural gas is more than its use each year
3) Oil production in Sidurian oil fields is increasing at a steady pace.

As the conclusion depends on the continuation of trends in fuel production and usage, first we need to understand these trends.

Natural gas: Production of natural gas > its use

As the requirement of natural gas is less than its production, the continuation of this trend is likely to reduce the reliance on foreign sources for natural gas.

As for oil, we know that oil production is increasing at a steady pace; however, unlike the requirement of natural gas, the requirement of oil is not known to us.

If the rate of increase of requirement of oil exceeds or is same as the rate of increase of production of oil, it’s unlikely that Siduria's reliance on foreign sources for fuel will decline soon.

Thus the argument underlies the assumption that

The rate of increase of requirement of oil is lower than the rate of increase of production of oil.



If we negate option C, we get:

At least one fuel other than natural gas is expected to be used as a replacement for oil in Siduria.

If I take your example, it means that bioenergy is expected to be used as a replacement of oil. This implies that requirement of oil may decline. Thus, the conclusion doesn't fall apart.

Note: we cannot add information about demand and production of bioenergy. We need to observe the impact of the option in its given form.

Hope this helps!
Dolly

egmat : Request your help on this.

I want to understand why B is not a correct option. Let me state my method of reasoning here :

If we negate the statement B, it states that :
Domestic production of natural gas is rising slower than its domestic production of oil.

Now, since the all heating systems will be converted from oil to natural gas, the demand will increase for natural gas and demand for oil will decrease. If the production of natural gas doesn't keep up with the demand, Siduria would need to import more oil. The excess production of oil will not help as its demand will reduce.

So, this definitely destroys the conclusion.

Can you help me understand the flaw of this reasoning?

Hi there,

B. Domestic production of natural gas is rising faster than is domestic production of oil in Siduria. Irrelevant as is already stated in the form of the premise,
Siduria already produces more natural gas each year than it burns, and oil production in Sidurian oil fields is increasing at a steady pace.

Hope it answers your query.

A. In Siduria the rate of fuel consumption is rising no more quickly than the rate of fuel production. - If the rate of fuel consumption is greater than rate of fuel production, then the country would still have to depend on foreign sources of fuel since it cannot match the energy requirements using its own sources. In order to establish the conclusion, we need to assume (A). Hence, (A) is the right answer choice.
B. Domestic production of natural gas is rising faster than is domestic production of oil in Siduria. - irrelevant to the conclusion drawn.
C. No fuel other than natural gas is expected to be used as a replacement for oil in Siduria. - the conclusion is not focused on oil per se; rather, it is focused on reducing dependency on foreign energy sources.
D. Buildings cannot be heated by solar energy rather than by oil or natural gas. - irrelevant to the conclusion drawn.
E. All new homes that are being built will have natural-gas-burning heating systems. - irrelevant to the conclusion drawn

GMATNinja daagh please explain how you would eliminate the rest of the options other than A?

I'll take you through my thought process at every step. First I read the question and the passage:



So it's an assumption question.

Then I untangle the argument. I try to pinpoint the conclusion first. Here the conclusion is: "if trends continue, Sid reliance on foreign fuel drops soon."

Why does this author think that? Well, they've converted heating systems from oil to gas, and they produce surplus gas each year, and their oil production is increasing. They have relied on foreign oil, though.

Okay so I get the logic. "They've had to import oil, BUT they switched heating from oil to gas. They have extra gas, and their domestic oil production is going up, SO, they won't need to import as much fuel in the future."

So assumption questions are about what ruins the argument. It would ruin this argument if foreign fuel (most likely oil) was increasing in other things besides heating enough to cancel out the benefits of their heating system switch and oil production increases. Or, if this heating system switch ate up all their natural gas, and they had to start importing that.

So the assumption must show that these things won't happen: increases in fuel use that cancel out these benefits.

So, to the answers:



This is definitely tempting--it talks about fuel consumption not increasing enough to cancel out the increase in fuel production. That's very close to what I was thinking.



This is an irrelevant comparison. I don't care which type of fuel increase is happening more in Siduria. I care that fuel use of any kind isn't overtaking the fuel it produces.



Negation test: a fuel other than gas is expected to replace oil. That doesn't ruin the argument. Could even be good for the argument. So C is not necessary for the argument, eliminate.



Similar reason to C. If buildings can be heated by solar... okay. Maybe they'll do that? If they don't, it doesn't affect the argument, if they do, it only makes the argument better. So get rid of this.



The argument doesn't rely on all new homes using natural gas. The fact that some heating systems are switching from oil to gas will mean they won't have to use as much oil as they have before. The question is--will the need for oil in other areas increase enough to undo this change? But E doesn't deal with that. So eliminate.

Answer must be A.

Here are some good resources for CR Assumption family:





The big key is identifying the pieces of the authors logic and pinpointing what possibilities would ruin that argument, and interpreting how the answers deal with--or don't--those things.

Assumption for the argument?

Eliminate options C,D and E since these refer to irrelevant references or factors that are inconsistent with the argument.

B states domestic production of natural gas is rising faster than that of oil. This point is incorrect since argument mentions that Siduria already produces more natural gas.

A refers to rate of consumption and this is correct, since argument does mention about conversion from oil to natural gas resource usage while oil production in Sidurian oil fields is increasing at a steady pace.