During the last 18 years, the number of people who live or work in the

Question

During the last 18 years, the number of people who live or work in the Dry river Valley, which is prone to flash flooding, has continually increased, as has traffic on local roads and bridges. However, the number of people caught in flash floods has decreased, even though the annual number of floods has increased slightly.

Which of the following if true, best explains the decrease described above?

(A) Flash floods are more likely to happen in the first hour of a rainstorm than afterward.

(B) Flash floods killed some people in the dry river valley in every one of the last 18 years.

(C) Better meteorological technology, combined with a better understanding of the conditions conducive to flash flooding has increasingly improved local authorities' ability to predict when and where flash floods occur.

(D) Many people work in the dry river valley but live elsewhere.

(E) A law that went into effect 18 years ago mandated that all new homes built in the valley be built on raised foundations, making those homes much less susceptible to flood damage.

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Basilio2 · Answer

I'm like 90% sure the answer should be C

Abdelaali91 · Answer

(A) does not provide any relevant explanation for the observed events

(B) same as A

(C) Correct, this means people will likely prevent being caught in the floods and have time to evacute to a safer place

(D) Already stated in the argument
(E) People woul still be caught in the floods, does not explain the decrease.

Bunuel · Answer

Official Explanation:

C

Step 1: Identify the Question Type

This is an Explain question. We can anticipate seeing a paradox or unusual coincidence described in the stimulus. Our task is to resolve the seemingly disparate pieces of information in order to explain the anomalous result.

Step 2: Untangle the Stimulus

The stimulus tells us about two increases—the number of people and the number of flash floods—in the Dry River Valley. The keyword “However” signals the seeming discrepancy: despite those increases, the number of people caught in flash floods has gone down. Let’s think critically about how we can reconcile these facts.

Step 3: Predict the Answer

Sometimes we can know exactly what the right answer choice is going to say, but that’s rare for Explain questions. Here, the stimulus involves numbers (of residents, floods, and flood victims), but it doesn’t state any actual values. Picking Numbers can help us visualize the situation in the stimulus. Pick numbers that are permissible and manageable. Let’s say that 18 years ago, there were 1,000 people, 10 floods, and 100 flood victims in the valley. Following the information in the stimulus, let’s say there are now 2,000 people, 20 floods, and 50 victims.

https://gmatclub.com/forum/download/file.php?id=59746

This shows that the floods are now less dangerous.

https://gmatclub.com/forum/download/file.php?id=59747

The correct answer will explain this change. It will provide a reason why the floods have been less dangerous.

Step 4: Evaluate the Choices

(C) gives us the explanation we need: more accurate advance notice of floods allows local authorities to better prevent people from getting caught. (A) may be true of flash flooding in general, but it doesn’t give us any difference between the floods now and those 18 years ago. (B) is outside the scope of the question, which deals with people caught in the floods, not people killed by them. (D) doesn’t explain the difference either, as there’s no reason to think that flash floods somehow selectively avoid commuters. (E) is also out of scope, since the argument does not focus on property damage.  Choice (C) is correct.

During the last 18 years, the number of people who live or work in the

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GMAT Critical Reasoning (CR) Questions

During the last 18 years, the number of people who live or work in the

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