Question 107·Medium·Central Ideas and Details
Engineers in Chile are testing a new desalination system powered entirely by solar energy. The compact device uses mirrors to heat seawater, turning it into steam that condenses into fresh water. The team hopes the low-cost setup will make clean drinking water available to remote coastal villages that lack reliable electricity.
According to the passage, what is the main purpose of the new desalination system?
For main purpose questions in short passages, first identify any sentence that directly states a goal or hope (look for verbs like "aims," "hopes," or "seeks"). Paraphrase that sentence in your own words, then scan the answer choices to find the one that best matches your paraphrase without adding new ideas. Quickly eliminate choices that focus on minor details (tools, methods, locations) or introduce topics the passage never mentions, and choose the option that captures the overall aim described by the author.
Hints
Find where the author explains the goal
Look for words or phrases that show what the engineers "hope," "aim," or "intend" to do with this system, not just how it works physically.
Focus on the final sentence
Pay close attention to the last sentence of the passage, beginning with "The team hopes..." What exactly do they hope the system will do, and for whom?
Ignore extra details in answer choices
Several options mention ideas that appear in the passage (like mirrors, solar energy, seawater), but ask yourself: which option captures what the engineers want to achieve overall, rather than describing a tool, a side effect, or an unrelated task?
Step-by-step Explanation
Identify what the question is asking
The question asks for the main purpose of the new desalination system. That means you should look for why the engineers are testing it or what they hope it will achieve, not just how it works.
Locate the key sentence about the purpose
In the last sentence, the passage says: "The team hopes the low-cost setup will make clean drinking water available to remote coastal villages that lack reliable electricity." This directly states what the team wants the system to accomplish.
Paraphrase the stated purpose
Put that key sentence into your own words: The engineers want this cheap, solar-powered system to give people in remote coastal villages access to clean, drinkable water even though they don’t have dependable electricity.
Match the paraphrase to the answer choices
Now compare that paraphrase to the options. Only A) Provide affordable drinking water to remote coastal communities. restates the idea of making clean (drinking) water available to remote coastal villages with a low-cost system, so A is the correct answer.