原帖由 prozzy 於 2007-5-18 23:05 發表。 
! p3 W) G+ m3 J( s公仔箱論壇the answer is -$97 for sure.
$ D$ l& _" z' O @8 @# K, a2 ^1 fThink about it this way
( n' c+ O/ X/ ltvb now,tvbnow,bttvb1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
' Q1 @: Y- F7 G0 Z5 U2) Now, the owner discovered that the 100 bucks is fake. You can th ... % n0 `6 V$ b: O5 T5 \9 X3 ^( M7 f$ C5.39.217.768 Q# @/ E8 i$ q9 A3 F: [/ \
2 P$ x" X- {- _! D3 B5.39.217.761) very good, it the 100 bucks is real, your answer is correct, but it is fake, so your answer is wrong
- u. j$ y" B4 R( n 公仔箱論壇# ?3 C! n) S* n b1 ?+ D4 l! t# T7 d
think about it, when the bill is fake, and he gave him $79 change back, that is -79 already, it means the 100 on his hand is equal to 0 (Zero), how did he makes profit when he got a fake bills, then he need to pay another real 100 dollars bill to his neighbor, that another -100, plus the product he lost, thats another 18 dollars, Do Not Even Mention the 3 dollars, there is no profit he can make when he got a fake bill.公仔箱論壇/ x' ?. r. o# r2 G
; z* n3 l! j+ j* u& A' |0 H {I know the answer becoz it really happening to my friend in his store in real LIFE, it can not be wrong. |