The company president's conclusion is: "we can also say that the number of salespeople passed over for these awards has similarly declined." Why? because the number of top salespeople receiving the award of free merchandise has declined markedly over the past 15 years, and the award criterion at present is membership in the top third of sales.
Remember that this is a Strengthen with Sufficient Premise question. Remember that a sufficient premise is sufficient for a conclusion, if and only if the existence of the premise guarantees or brings about the existence of the conclusion.Therefore, we need to find the premise that 100% guarantees the conclusion. The way you want to attack these answer choices is two-pronged. Ask yourself, does it strengthen? If it doesn't, then cross it out and continue to the next answer choice. If it does strengthen, however, then ask yourself whether or not the premise 100% guarantees the conclusion.
Answer choice (C) is the correct answer because it both strengthens and guarantees the conclusion of the argument. If the criterion for the past fifteen years has been the same for selecting its award recipients, then it strengthens the president's conclusion that the number of salespeople passed over the awards has similarly declined, since that means that the overall number of salespeople has declined, so proportionately each category - people who received an award and people who were passed over - would decline, as well. This also guarantees the conclusion, since it means that the overall number of salespeople has declined as opposed to requirements for the award becoming stricter. So, if the number of people has gotten smaller, the bottom two-thirds of the group will have a smaller number than it previously had, as well.
A quick numerical example will clarify this. Imagine that today, 2 people received the free merchandise award. This would mean that 4 people were passed over (i.e. 2/6 = 1/3). Now imagine that fifteen years ago, 3 people received the free merchandise award. If the criterion used by Wilson's for selecting its award has remained the same for the past fifteen years (i.e. top third), this would mean that 6 people were passed over (i.e. 3/9 = 1/3).
Hope that was helpful! Please let us know if you have any more questions.
MelissaAugust 24, 2016
Why is answer choice e incorrect? I understand why c is correct, but what makes it better than e?
MehranAugust 30, 2016
@Melissa this is a Strengthen with Sufficient Premise question, so we are looking for the answer choice that 100% guarantees the conclusion (i.e. the super premise).
(E) is incorrect because even if Wilson's calculates its salespeople's sales figures in the same way it did fifteen years ago, that does not guarantee the company president's conclusion that "we can also say that the number of salespeople passed over for these awards has similarly declined."
For example, fifteen years ago, even though Wilson's calculated its salespeople's sales figures in the same way as it does today, the criterion for the award could have been different.
Notice that (C) addresses this issue and, by doing so, guarantees the conclusion.
See @Naz's explanation above for a numerical example to prove this.
Hope this helps! Please let us know if you have any other questions.
