­Due to drought and other agricultural difficulties, the price of

Premise: ­The principal idea is since price of Cotton is rising
Conclusion: Rayon must be added to reduce the price.

Prethinking: But that would work IFF Rayon costs less than Cotton else it'll not work. ( like in alligation mixing adulterant to lower prices etc )

A. Correct

For wrong choices that were selected B and C:  Rising of price is not same as Rising above the price of cotton.

Rayon price may rise or fall due to market pressures but it woould still makes clothes cheaper as long as price is below cotton's cost.­

Option A has got a potential discrepency:
It says that : The price of rayon will not soon exceed the price of cotton.

If X does not exceed Y, it can still become equal to Y.
With this logic, if the price of rayon even becomes equal to that of cotton, the prices of cloth are not going to stay low.

­It's true that, "if the price of rayon even becomes equal to that of cotton, the prices of cloth are not going to stay low."

At the same time, it is also true that, for the argument to work, it must be true that "The price of rayon will not soon exceed the price of cotton." After all, if the price of rayon will soon exceed the price of cotton, then the conclusion is not supported.

So, choice (A) is necessary for the argument to work.

We could say that the argument requires both assumptions, that the price of rayon will not exceed the price of cotton and that the price of rayon will not equal the price of cotton. Either one of those would be a correct answer.

Understanding the argument - 
­Due to drought and other agricultural difficulties, the price of cotton has skyrocketed, hitting all-time highs. - Fact. Causal relationship. 
Therefore, in an attempt to keep clothing prices low, clothing manufacturers are likely to blend more rayon into their garments. - Conclusion. 
Goal - to keep clothing prices low
Plan - clothing manufacturers are likely to blend more rayon into their garments.

The reasoning above relies on assuming which of the following?

We need to find the missing premise, minimum condition, or assumption. 

A. The price of rayon will not soon exceed the price of cotton. - negation shatters the conclusion.

B. The price of rayon is not subject to changes due to any of the agricultural difficulties that cotton is subject to. - when negated, it says "subject to changes." But change can be low or higher. Ambiguous effect. Distortion. 

C. Increasing demand for rayon is unlikely to cause its price to rise. - Say the price of cotton increased from $10 per unit to $100 per unit. And on Rye, it's likely to increase from 0.5 cents to $1. Does the negation shatter the conclusion? No. 

D. Consumers are unable to distinguish between clothes made of pure cotton and those made of blends of cotton and rayon. - out of scope. 

E. Making clothes from blended fabrics involves processes identical to those involved in making clothes from pure cotton.­ - out of scope. 

Can someone let me know why C can't be the answer. I thought about the question like this:

If the goal is to "keep clothing prices low", then any price increase in rayon will increase clothing prices. The price of rayon doesn't have to exceed the price of cotton, in order for the clothing price to be not low. If the price of rayon was the price of cotton minus a dollar, the price of clothing could still be high. Therefore, woudn't C be the stronger answer?

AjiteshArun
Won't the negtion of B be - The price of rayon is subject to changes due to ANY of the agricultural difficulties that cotton is subject to.

[quote="ChiranjeevSingh"]­Here's a brief explanation addressing popular options A, B, and C.

All three - A, B, and C - are strengtheners. Only A is an assumption since its negation breaks down the argument. Neither negation of B nor negation of C breaks down the argument.

Negation of A: The price of rayon will soon exceed the price of cotton. - If the price of rayon becomes higher than the price of cotton, how will it make sense for clothing manufacturers to blend more rayon?! In such a case, they will rather use more of cotton. So, the negation of A breaks down the argument.

Negation of B: (This is tricky) The price of rayon is subject to changes due to SOME of the agricultural difficulties that cotton is subject to.

We get to know that SOME of the agricultural difficulties will also apply to rayon. So, we can expect SOME increase in the price of rayon. However, SOME increase does not break down the argument based on skyrocketing prices of cotton.

If the option had been "The price of rayon is not subject to changes due to some of the agricultural difficulties that cotton is subject to."

Then its negation would be "The price of rayon is subject to changes due to ALL of the agricultural difficulties that cotton is subject to."

So, all the agricultural difficulties that apply to cotton also apply to rayon. In this case, the argument breaks down.

However, the negation of original option B DOES NOT break down the argument.

Negation of C: Increasing demand for rayon is likely to cause its price to rise.

Just as in the case of B, some price rise WILL NOT break down the argument.

If option C had been "Increasing demand for rayon is unlikely to cause its price to rise to the same extent as the price of cotton."

Then its negation would be "Increasing demand for rayon is likely to cause its price to rise to the same extent as the price of cotton."

If both prices are rising to the same extent, we don't have a reason to expect clothing manufacturers to switch from cotton to rayon. Thus, the argument breaks down in this modified version of option C.

However, the argument doesn't break down in the case of negation of the original option C. Thus, option C is not an assumption.[/quote]

Hi Kavicogsci,

Not quite. We can negate B like this: The price of rayon is subject to changes due to at least one agricultural difficulty that cotton is subject to.

To understand this, let's take a quick example. Say there are three things { A, B, C } and something else (like price, demand, etc.) is NOT subject to any of them. Here's what that would look like: { A, B, C }.

The negation of this would cover the other possibilities: { A, B, C }, { A, B, C }, { A, B, C }, { A, B, C } ... { A, B, C }.

Another way to think through this is that option B effectively tells us that there is NO overlap between the two sets. One extreme example of that would be when the price of rayon is not affected by anything. Another example:

1. Rayon is subject to { X, Y, Z } and cotton is subject to { A, B, C }. There is no overlap.

2. The negation is that there is either partial or complete inclusion of one set in the other. For example, rayon { X, Y, A} and cotton { A, B, C }.

Premise:
­Due to drought and other agricultural difficulties, the price of cotton has skyrocketed, hitting all-time highs.

Conclusion:
Therefore, in an attempt to keep clothing prices low, clothing manufacturers are likely to blend more rayon into their garments.

Assumption will likely be something like: Rayon is cheaper than cotton.

A. The price of rayon will not soon exceed the price of cotton.

Correct. This is an assumption. The timeline is of near future. Our argument's timeline is also near future - Because of high cotton prices, clothing manufacturers are likely to blend more rayon into their garments. They will likely blend rayon only if rayon prices will not exceed cotton prices.

B. The price of rayon is not subject to changes due to any of the agricultural difficulties that cotton is subject to.

We do not need to assume that rayon prices are not subject to any of the agricultural difficulties that cotton is subject to. It is possible that drought affected rayon prices too but to a lower extent. As long as rayon prices are lower than cotton prices (even if current rayon prices are higher than past rayon prices) the manufacturers are likely to mix more rayon. Hence it needn't be true that price of rayon is not subject to changes due to current difficulties.


C. Increasing demand for rayon is unlikely to cause its price to rise.

Again, as long as its price stays below cotton price, adding more rayon remains feasible. The comparison is between cotton and rayon prices, not between old rayon prices and new rayon prices.

D. Consumers are unable to distinguish between clothes made of pure cotton and those made of blends of cotton and rayon.

Not necessary. First of all we have no discussion of "pure cotton" clothes. The argument only tells us "manufacturers are likely to blend more rayon into their garments"
Even if we were to discuss pure cotton vs blend, and if consumers are able to distinguish, manufacturers may choose to use more rayon to keep pricing low. Also, there is nothing that says that consumer dislike more rayon in clothes.

E. Making clothes from blended fabrics involves processes identical to those involved in making clothes from pure cotton.­

Not necessary. Manufacturers could alter their processes if required. We are not given that altering processes is more expensive than using cotton currently.

Answer (A)

Discussion on identifying assumptions: https://youtu.be/O0ROJfljRLU