the answer is -$97 for sure. + e; w0 l$ x8 g3 r) j
Think about it this way ! t2 m9 {: m0 g% m, A- S3 v
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)tvb now,tvbnow,bttvb) V- }. J1 Q# Y; K* ^, [
2) Now, the owner discovered that the 100 bucks is fake. You can think this as a lost of $100. therefore the overall gain is $3-$100 = -$97 |
發表於 2007-5-16 03:12 AM
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發表於 2007-5-19 03:21 PM
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發表於 2007-5-21 03:49 AM
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