prozzy

the answer is -$97 for sure.
7 A( e/ i. E8 J* o( e+ S* x1 uThink about it this way
$ @2 p  X) y1 `# q$ P, o1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)TVBNOW 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。5 V+ K) U5 t' F( g& z4 w1 G
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