Hi Anaira Mitch,
This DS question isn't about doing math so much as it is about understanding the logic involved (and whether you have enough information to properly answer the question).
We're told that a 0.5% tax is required from both the buyer and the seller of a house. We're told that Colleen sold a house and bought a different house. We're asked for the TOTAL tax that she paid on the two houses. To answer this question, we need to know what the prices of the two houses were.
1) Colleen's old home had a sale price of $169,500.
With this Fact, we could figure out the tax on the old home, but we know nothing about the price/tax of the new home.
Fact 1 is INSUFFICIENT
2) Colleen's new home had a sale price 20% greater than that of her old home.
This Fact tells us nothing about the two prices, so there's no way to determine the tax paid on either home.
Fact 2 is INSUFFICIENT
Combined, we know...
-the price of the old home ($169,500), so we can figure out 0.5% of that.
-the price of the new home is 20% greater than ($169,500), so we could figure out THAT price AND the 0.5% tax associated with it.
With the two taxes, we can add those two values and answer the given question.
Combined, SUFFICIENT
Final Answer: C
GMAT assassins aren't born, they're made,
Rich
