LR Drill Set 3, Question 6
A region wherein all telephone numbers now have(73 more words not shown)
The reasoning in the argument(5 more words not shown)
- Atakes for granted(17 more words not shown)
- Bimproperly relies on(7 more words not shown)
- Ctakes for granted(13 more words not shown)
- Doverlooks the possibility(9 more words not shown)
- Eoverlooks the possibility(11 more words not shown)
Reading the argument
How many phone numbers are there, and how often are those numbers called? Those aren't the same count.
At first, keeping the old area code for the larger group sounds like a way to minimize disruption. But imagine a business phone ringing all day while a home phone gets only a few calls. Changing the business number could create many more opportunities for mistaken dialing, even though it is only one number.
That's the problem with using the number of residential lines to predict the number of wrong calls. Suppose 100 homes receive two calls each per day, while ten businesses receive 100 each. The homes have more numbers, but the businesses receive 1,000 calls compared with 200. We would need to consider call volume before deciding which change produces fewer mistakes.
What we’re looking for
There may also be costs to businesses updating advertisements and records. Those are possible concerns about the recommendation, but the reason offered here is specifically fewer wrong numbers. The flaw answer should challenge the assumption that more numbers means more opportunities for wrong dialing.
Working the answers
- A
The passage states that the region is being split. It doesn't establish that the old code lacks enough numbers for more than half the region, and that numerical capacity claim isn't needed to choose who keeps it. The argument concerns the consequences of two possible assignments within the planned split.
- B
Residences and businesses are meaningful categories here. We can understand which is which and still find the reasoning flawed. The missing information is how frequently they receive calls, not a clearer definition of the distinction between them.
- C
The recommendation can allow for future growth. Nothing in its reasoning requires both sections to remain the same size forever. The immediate problem is that it uses the current number of telephone numbers as its basis for a prediction about wrong calls without addressing their relative use.
- DCorrect
Businesses might receive many more calls per number than homes do. Then changing the smaller group of business numbers could expose more calls to an area-code mistake. Our numerical example shows how that can happen without disputing that residences have more numbers. D identifies the omitted factor that matters to the argument's own goal.
- E
Adding several codes would be another plan. But the argument compares giving the existing code to residences with giving it to businesses under a two-region split. Merely pointing out a third possible code doesn't explain why the stated reason fails to favor one of those two assignments. Call frequency does.
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