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100 points for $49 worth of Veritas practice GMATs FREE VERITAS PRACTICE GMAT EXAMS Earn 10 Points Per Post Earn 10 Points Per Thanks Earn 10 Points Per Upvote ## OG DS tagged by: rashedhbs ##### This topic has 1 expert reply and 1 member reply ## OG DS Of the 230 single-family homes built in City X last year. how many were occupied at the end of the year? (1) Of all single-family homes in City X, 90 percent were occupied at the end of last year. (2) A total of 7,200 single-family homes in City X were occupied at the end of last year. E Newbie | Next Rank: 10 Posts Joined 17 Aug 2018 Posted: 9 messages Hi, Of the 230 single-family homes built in city X last year how many were occupied at the end of the year? Looking at both the statement, we may think that they are sufficient, see right away but the statements only give us information about the occupancy of single-family homes in city X. None of the statements talks about the occupancy of the newly built homes. Therefore, even by combining both options we cannot reach the answer. So, the answer is E. Just to add more clarity. Let’s look this by forming equations. From the question we get: Total Homes in City X = [Homes built before last year] + 230(home built last year) We are asked how many of the 230 homes were occupied. So we also have equation: 230 = [Occupied Homes Built last year] + [Unoccupied Homes Built last year] Question: Occupied Homes built last year? Statement I is insufficient: Of all single-family homes in City X, 90 percent were occupied at the end of last year. It talks about the entire single family homes, we want something very specific which is built last year. Total Homes in City X = Total Occupied (90%) + Total Unoccupied (10%) No information about the newly built homes last year. So Insufficient. Statement II is insufficient: A total of 7,200 single-family homes in City X were occupied at the end of last year. Similar to statement I, it talks about the entire single family homes. Total Homes In City X = 7200 + Total Unoccupied Insufficient. Even combining these two statements it is impossible to get any information on the homes built last year to answer the question. So the answer is E. Hope this helps. ### GMAT/MBA Expert Elite Legendary Member Joined 23 Jun 2013 Posted: 10071 messages Followed by: 494 members Upvotes: 2867 GMAT Score: 800 Hi rashedhbs, To start, you would like receive more of a response if you make sure to post your questions in the proper forums. For example, the DS forum can be found here: https://www.beatthegmat.com/data-sufficiency-f7.html We're told that 230 single-family homes that were BUILT in City X last year. We're asked for the number (of those 230) that were occupied at the end of the year. This question can be approached in a number of different ways. It's more of a 'logic problem' though, so you can beat it with some basic notes and TESTing VALUES (as needed). 1) Of all single-family homes in City X, 90 percent were occupied at the end of last year. From the prompt, we don't know how many single-family homes existed BEFORE the 230 additional single-family homes were built. Thus, we have no way to determine what the TOTAL number of single-family homes was - nor what 90% of that number would be - nor how many of the 230 new single-family homes were occupied. Fact 1 is INSUFFICIENT 2) A total of 7,200 single-family homes in City X were occupied at the end of last year. Fact 2 gives us an 'absolute' number of single-family homes that were occupied, but we have no way of knowing how many of the 230 single-family homes that were built last year are included in that 7200. Fact 2 is INSUFFICIENT Combined, we know... -Of all single-family homes in City X, 90 percent were occupied at the end of last year. -A total of 7,200 single-family homes in City X were occupied at the end of last year. With these two pieces of information, we can determine the TOTAL number of single-family homes in the city. (.9)(X) = 7200 --> X = 8000. This total includes the 230 additional homes that were built. However, we still have no idea how many of THOSE homes were occupied, so the answer to the question could be anything from 0 to 230. Combined, INSUFFICIENT Final Answer: E GMAT assassins aren't born, they're made, Rich _________________ Contact Rich at Rich.C@empowergmat.com • 5-Day Free Trial 5-day free, full-access trial TTP Quant Available with Beat the GMAT members only code • 1 Hour Free BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • FREE GMAT Exam Know how you'd score today for$0

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