the answer is -$97 for sure.
* j7 t$ w$ B# [$ x, ~( o) t9 iThink about it this way
. j8 H7 C2 Q. C5 V. |0 b1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)2 S( H; d3 e) K2 r# T9 }* _
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
| 
發表於 2007-5-19 03:21 PM
| 
發表於 2007-5-21 03:49 AM
| 