Overview: Assumption Questions | Verbal for GMAT PDF Download

Assumption questions require you to identify the hidden connection between a question's starting point and its conclusion. Assumptions are essential in comprehending and challenging arguments, making them significant in certain types of Critical Reasoning questions.

What are Assumptions Questions?

Find the Assumption questions ask you to identify an assumption upon which the argument is based. The question stem most commonly uses the words assumption or assume, though it may also use other words such as flaw or questionable, and it may take a number of forms:

Which of the following is an assumption on which the commissioner's plan depends?
The argument above relies on which of the following assumptions?

Premises + (Assumptions) = Conclusion

• A premise is the starting point of the argument.
• The conclusion is what the author wants you to believe by the end of the argument.
• The assumption is the missing link between the premise and the conclusion. 

When dealing with arguments, it's important to note that they don't just state the conclusion is true; rather, they assert that the evidence in the argument logically leads to that conclusion. Assumptions act as a crucial link between the evidence and the conclusion, making them necessary for the conclusion to be considered valid.

Assumptions fill a gap in the argument. If we insert a correct assumption in the argument, it makes it stronger.
For example:

The gap is represented by the arrow.

Identify the Assumption

Isolating an assumption is an important skill. Look at this argument:

Hawaii is a place with beautiful scenery. Therefore, people there must have trouble concentrating for any length of time at all.

• The premise is “Hawaii is a place with beautiful scenery.” (We can safely assume that at least 99 out of a hundred people would agree with that!) Hawaii is the specific, so you can omit that—the final premise has to do with a “place with beautiful scenery.”
• The conclusion is “trouble concentrating.”
• The assumption must provide a link. If we put those together with a strong logical connection, we get this assumption: “People in places with beautiful scenery generally have trouble concentrating.” Even though it’s a little absurd, that’s a possible way to state the assumption!

Use the Negation Test to Verify the Assumption

If you want to check if your guess is really right, you can use the Negation Test.  It's a simple trick: try saying the opposite and see if what you thought is still true. It's a powerful technique for figuring out the hidden assumptions in arguments.

• If you can think of a situation where the conclusion is still true even after changing a statement to its opposite, then that original statement is not a necessary assumption for the argument.
• If changing a statement to its opposite creates a powerful objection that destroys the argument and makes the conclusion impossible to support, then the original statement is indeed an assumption of the argument.

Example

Alex likes this movie.  Therefore, Betty will like it. 

Find the assumption of the argument

A. Both Alex & Betty liked the same movie last year
B. Carla didn’t like this movie, and last year, she & Betty liked the same movie.
C. Betty likes the movies that Alex likes.

Let’s just apply the Negation Test to all three answers:

The negation of (A): Alex & Betty didn’t like the same movie last year —- a vaguely weakening objection, but that was last year, and this is this year: what Betty likes now might be the same as what Alex likes now.  It’s at least conceivable that the negation of (A) could be true and yet the conclusion to this argument would hold.   Therefore, (A) is not an assumption of the argument.

The negation of (B): Carla liked this movie, and last year, she & Betty liked the same movie. OR Carla didn’t like this movie, and last year, she & Betty didn’t liked the same movie.  —- Either way, this answer just introduces the variable of another person.  We don’t know how fickle Carla is, and whether her taste overlaps in any meaningful or consistent way with Betty’s.  Therefore, it is possible that either of these negations could be true and the conclusion would still hold.   Therefore, (B) is not an assumption of the argument.

The negation of (C): Betty doesn’t like the movies that Alex likes. —- Hmm, if this is true, and if Alex likes this movie, it seems necessarily to imply that Betty won’t like this movie!  This directly contradicts the conclusion of the argument.   Negating (C) absolutely torpedoes this argument, so (C) must be an assumption. 

Solved Examples

Q1: Most people can gain vitamin C from fruits such as oranges and cantaloupes. People with Laestrygonian Disease have weakened digestive systems that cannot digest fruit or vitamin supplements. The easiest foods for these people to digest are grains such as rice and barley. Regular intake of vitamin C would be extremely beneficial to those who suffer from Laestrygonian Disease, so scientists have figured out a way to create “fortified rice” by infusing rice with high doses of vitamin C. This fortified rice will provide great benefit to those with Laestrygonian Disease.
Which one of the following is an assumption on which the conclusion depends?
 (A) Eventually, this fortified rice will be the optimal way for most people to have a regular intake of vitamin C.
 (B) The problems that folks with Laestrygonian Disease have digesting fruit are different from their problems digesting vitamin supplements.
(C) People with Laestrygonian Disease will not be unable to assimilate the form of vitamin C that is present in the fortified rice.
(D) Only people whose diets consist largely of grains would be able to derive benefit from the vitamin C in the fortified rice.
(E) Vitamin C is the only nutrient which can be infused into rice in such high quantities without compromising the nutritional integrity of the vitamin.
Sol:
If folks with Laestrygonian Disease cannot assimilate the Vitamin C in the rice, then it won’t help them, and eating the fortified rice will not provide them any particular benefit. If we negate this option, it shatters the argument. This is a true assumption.
(A) This may be true, although I am skeptical that any human-made improved food would be better than the fruits designed by Nature! Regardless, whether this is true or not does not have any bearing on how helpful the fortified rice will be for the folks with Laestrygonian Disease. This option is incorrect.
(B) This is intriguing. Let’s negate this. Suppose it were the exact same problem, say, the exact same missing enzyme, that made it impossible to digest both fruit and vitamin supplements. Then what? Would that mean they also couldn’t digest the fortified rice, or get the vitamin C they need from it? We cannot say. It’s conceivable that the argument could still work, so negating this does not destroy the argument. This is not an assumption.
(D) Let’s negate this. Suppose the fortified rice benefits everyone—even the no-carbs fanatic who hasn’t touched carbs in a decade: even when this person breaks his carb-fast and has the fortified rice, he has benefit from it. What then? Whether these other people benefit or not from the fortified rice has no bearing on whether it helps the folks with Laestrygonian Disease. This choice is incorrect.
(E) Let’s negate this. Suppose we can infused dozens of other vitamins and minerals into the rice, all with high nutritional yield. That would only be good for the folks with Laestrygonian Disease—the more vitamins, the better! It certainly would not impact whether these folks derived any benefit from the vitamin C in the rice. This choice is incorrect.
The answer is (C).

Q2: In an effort to reduce carbon emissions, a new type of biofuel, called EcoFuel, has been developed from algae. This biofuel is intended to replace traditional fossil fuels in vehicles. Advocates argue that EcoFuel will significantly reduce the overall carbon footprint of vehicles since algae absorb carbon dioxide as they grow. Therefore, using EcoFuel in vehicles is expected to be a major step towards combating climate change.
Which one of the following is an assumption on which the conclusion depends?
(A) The production process of EcoFuel is more cost-effective than the extraction and refining of fossil fuels.
(B) Vehicles that currently use traditional fossil fuels can switch to EcoFuel without requiring major modifications.
(C) The use of EcoFuel will not lead to an increase in vehicle usage, thereby offsetting its carbon-reduction benefits.
(D) The carbon absorbed by algae during their growth is greater than the carbon emitted when EcoFuel is burned.
(E) Other sources of renewable energy cannot be as effectively used in vehicles as EcoFuel.
Sol:
The argument is that using EcoFuel will reduce the overall carbon footprint of vehicles and help combat climate change. For this to be true, it is essential that the carbon absorbed by algae during the production of EcoFuel is more than the carbon emitted when EcoFuel is used. If we negate this option (D), the argument falls apart because if the carbon emitted is more than or equal to the carbon absorbed, using EcoFuel would not contribute to reducing the carbon footprint. This is a critical assumption.
(A) Whether EcoFuel production is cost-effective compared to fossil fuels is related to economic viability, not to its effectiveness in reducing carbon emissions. This is not an assumption on which the argument about carbon reduction depends.
(B) The requirement of vehicle modifications for using EcoFuel is not directly linked to the argument about its impact on carbon emissions. This is a practical consideration but not a foundational assumption for the argument's validity.
(C) The potential increase in vehicle usage is a factor that could impact the overall effectiveness of EcoFuel in reducing carbon emissions. However, the argument assumes that the usage patterns remain constant, making this not a core assumption of the argument.
(E) The comparison with other renewable energy sources is not essential to the argument about EcoFuel's effectiveness in reducing carbon emissions from vehicles. The argument focuses solely on the impact of EcoFuel, not on its relative efficacy compared to other energy sources.
Therefore, the correct answer is (D).

Q3: A recent study suggests that implementing a four-day workweek in companies can lead to increased employee productivity and overall well-being. The study posits that a reduced workweek allows employees more time to rest and engage in personal activities, which in turn boosts their focus and efficiency at work. Consequently, it's argued that adopting a four-day workweek could be beneficial for both employees and employers.
Which one of the following is an assumption on which the conclusion depends?
(A) Employees will use the extra day off to rest and engage in activities that enhance their well-being.
(B) Most companies have the technological infrastructure to support a more condensed workweek.
(C) A shorter workweek will lead to a significant reduction in operational costs for companies.
(D) Competitors will not take advantage of the reduced operational days to outperform companies that implement a four-day workweek.
(E) The overall market and economic conditions will remain stable, ensuring that a four-day workweek does not negatively impact business growth.
Ans: (A)
Sol: The argument is that a four-day workweek boosts employee productivity and well-being because the extra time off allows employees to rest and engage in personal activities. This conclusion depends on the assumption that employees will indeed use the extra day for activities that contribute to their well-being and rejuvenation.
(A) This is a critical assumption. If employees do not use their additional time off to rest and engage in beneficial activities, the supposed increase in focus and efficiency at work may not materialize.
(B) While technological support is important for any work structure change, it is not a direct assumption linked to the claim about increased productivity and well-being.
(C) Operational costs are a financial consideration but do not directly relate to the argument's focus on productivity and well-being.
(D) The potential competitive disadvantage due to reduced operational days is a concern but not an assumption on which the argument about increased productivity and well-being relies.
(E) Market and economic conditions are external factors that can affect any business model. However, the argument about the benefits of a four-day workweek assumes internal company dynamics rather than external market conditions.
The correct answer is (A), as the argument fundamentally assumes that the way employees spend their additional time off directly influences the claimed benefits.