The value of X that you calculated gives you all single families homes in City X. But the question ask you the number of single family homes built at the end of the last year out of the particular 230 single families homes that were built in city X.
Remember- out of the particular 230 homes - how many were occupied at the end of the last year?

So the answer is E.

The question asks - 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 choices, we see right away (without any calculations) that the options only give us information about the occupancy of single-family homes in city X. None of the options talks about the occupancy of the newly built homes. Therefore even by combining both options we cannot reach the answer.

Therefore the answer is (E).
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The answer is E.

GyanOne's explanation is good.
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+E, since both number of single family homes in the city.

Actually , Sentence correction skills would help us out here -if some of us havent understood the question part yet.

The question says about "of THE 230 single family homes- here, the determiner is THE and qualifies the noun 230 single family homes. So, the question is asking about only those 230 single family homes and thats all.
But both statements (St1 & St2) are giving info only abt total number of SF homes built last year. None of them are talking abt THE 230 single-family homes. ANS: E

My answer is E as well.

Though statement 1 is lucarative and tends to create a trap of assuming 90% of 230. However, one way to overcome that trap is to read statement 2

Ohh i got confused..thought its A.......

IMOE

OF THE 230 Single HOMES BUILT in city X last year,How many were occupied at the end of the year?

we have to calculate (Number of homes OF the 230 that were occupied at the EOY)

(1).

All Single Family Homes = X + 230
where X = OLD Single Family Homes that were built before LAST YEAR

So, statement says

0.9(X + 230) were OCCUPIED at EOY

=> 0.9X + 0.9*230 = > 90% of (230) were OCCUPIED LAST YEAR.

SUFFICIENT

Plz Advice

Rgds,
TGC

From the question we get:

Total Homes in City X = [Homes built before last year] + 230

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 is, Occupied Homes BUILT LAST YEAR = ?

Statement (1) gives us an entirely new equation that adds even more unknown variables:

Total Homes in City X = Total Occupied(.9) + Total Unoccupied(.1)

We can't do anything with this. Insufficient.

Statement (2) gives us the exact same information from Statement 1 in a different form

Total Homes In City X = 7200 + Total Unoccupied

Insufficient.

Even combining these two equations it is impossible to get any information on the homes built last year to answer the question, let alone which ones were occupied. So (C) is also insufficient.

Answer = E.

If you had 20 candies and I gave you 10 candies more.

Then end of week 1 only 10% of candies are left. . That means you ate 90% . Which mean only 3 candies are left.

Now are those 3 from initial 20 or are those 3 from newly bought ones?

Does this solve the question you raised?

Posted from my mobile device

Hi All,

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:

GMAT assassins aren't born, they're made,
Rich
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