Critical Reasoning (CR) | Re: The use of growth-promoting antibiotics in hog farming can weaken

Premise:
1. use of antibiotics in hog farming can weaken their effectiveness in treating humans.
2. smee is largest pork marketers, may stop buying pork raised on feed containing these antibiotics.
3. farmers who sell to Smee would certainly stop using antibiotics in order to avoid jeopardizing their sales.
4. smee has 60 % of market.

conclusion: So if Smee makes this change, it will probably significantly slow the decline in antibiotics’ effectiveness for humans.

Pre-thinking : if smee has 60% of market, which means 40% of the market is acquired by other marketers. if these 40% kept selling antibiotics pork then conclusion could not be achieved. Mind that this is a kind of pattern GMAT uses to make such kind of problems. Many problems are of this same framework. If something such as this need to stop, make sure others also not doing it.
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