prozzy

the answer is -$97 for sure.
) Z8 @+ k& f9 d: `3 v* x5.39.217.76Think about it this way
- X7 ]+ t3 a* ^- Y6 _; A) \+ QTVBNOW 含有熱門話題，最新最快電視，軟體，遊戲，電影，動漫及日常生活及興趣交流等資訊。1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
& Y7 Z1 U: v+ x% w4 S( `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