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:
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Rich
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