If you compound twice a year, you need to divide your annual interest rate by 2, and knowing that one thing alone lets you see that A is the right answer here.

But the math in this question is not proper math. The question tells us that Y represents some unknown value. They then write "0.0Y" in the answer choices, where we're meant to assume Y instead represents an unknown digit. It would be perfectly reasonable (correct, in fact) to assume 0.0Y means a product of 0.0 and Y. I say that interpretation is correct because if you read a question that says "k is a single digit integer between 0 and 9, and 2k > 17", then k absolutely does not represent an unknown units digit in the number '2k'. It represents an unknown value- the inequality tells us that 2 times k is greater than 17.
_________________

Don't think this is a GMAT type question. The answer is just the representation of compounded interest formulae, where we need to add inputs given in the question stem.

Thanks,
Chanakya

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________