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The percentage of households with an annual income of more than $40,000 is higher in Merton county than in any other county. However, the percentage of households with an annual income of $60,000 or more is highest in Sommer county.
If the statements above are true, which of the following can properly be concluded on the basis of them?
An inference question does not give us license to read between the lines. We need to be just as careful to stick to the information the passage provides to avoid jumping to wayward conclusions. Here, there are two counties, and we can sum up the information in the following manner.
Merton— highest percentage of household income > $40K
Sommer—highest percentage of household income ≥ $60K
That is it. We can appreciate right away that no upper limit has been set, just a lower limit in two separate cases.
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(A) No household in Merton county has an annual income of $60,000 or more.
This is too extreme. If you like numbers, keep things simple. Picture three households in each county with the following annual incomes:
Merton—$45K, $50K, $60K
Sommer—$30K, $60K, $65K
Of course, you have to make sure you keep the given information in mind. Merton has 3/3 households, or 100 percent, that earn
more than $40,000 but only one, or 33 percent, that earns
at least $60,000; Sommer has 2/3 households, or 67 percent, that earn more than $40,000, and those same two earn at least $60,000. We have stuck to the given information, and we have disproved answer choice (A) in the process.
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(B) Some households in Merton county have an annual income between $40,000 and $60,000.
We can make such an inference, not on the basis of what I came up with above, but because notice, again, that, in terms of income, the passage states
more than $40,000 and
$60,000 or more. Blink, and you might miss the distinction, but these two inequalities are not the same type. Since we know that Sommer county has the greatest percentage of households
at or above an annual income of $60K, but that Merton county has the greatest percentage of households
above an annual income of $40K, it must be true that
some households in the latter earn between $40K and $60K. I know that test-takers can be wary of
some, and with good cause: the word pops up in many answers that end up being wrong. At the same time, you never want to stop applying logic to a given answer choice simply because you see a certain word or expression. You still have to think.
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(C) The number of households with an annual income of more than $40,000 is greater in Merton than in Sommer county.
Do not conflate a
percentage with a
number. Take our sample from before, but
add a few more households to Sommer county:
Merton—$45K, $50K, $60K
Sommer—$30K, $60K, $65K,
$66K, $67K, $68KNow, it should be evident that
it can still be true that Merton county has the highest percentage of households above $40K (100 percent) without having the most households at or above that threshold—3, in my expanded example, versus 5 in Sommer county.
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(D) Average annual household income is higher in Sommer than in Merton county.
We cannot figure out an
average based on nothing more than a vague comparison between
percentages. Consider a different set of numbers that conform to the information from the passage:
Merton—$50K, $50K, $50K (average = $50K)
Sommer—$20K, $30K, $70K (average = $40K)
You do not have to go this far, though. To find an average, you need two pieces of information: 1) a sum (which we cannot possibly calculate); and 2) a total number of items to divide (which we do not know). Without either piece of information, we cannot possibly calculate the
average annual household income for either county.
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(E) The percentage of households with an annual income of $80,000 is higher in Sommer than in Merton county.
I hope you can appreciate by now that we know nothing about this new limit. Anything about the $80K mark is pure speculation.