please solve this one.

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by Brent@GMATPrepNow » Tue Sep 20, 2016 4:31 am
aarzoo wrote:What is the sum of the cubes of the even numbers from 20 to 40 (both inclusive)?
When posting questions, please include the 5 answer choices. In many cases, the fastest approach involves using the answer choices to our advantage.
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by [email protected] » Tue Sep 20, 2016 9:13 am
Hi aarzoo,

As Brent has already pointed out, having the 5 answer choices would be quite helpful in answering this question (and is often essential to solving certain Quant questions on Test Day). The answers can sometimes provide a hint as to how to best solve the problem or give you a way to avoid lengthy calculations.

With this prompt, we could very well have answers that are so 'spread out' that we can use estimation to get to the correct answer. There's also the possibility of a built-in Number Property (involving the units digits of the squares of each of those even numbers) that we could use - along with some basic arithmetic - to get to the correct answer.

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