the answer is -$97 for sure.
: V$ ^4 }3 ~5 e( T3 X0 l& m$ btvb now,tvbnow,bttvbThink about it this way 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。; L9 D- M) m3 }9 o
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)4 W0 y, y$ [4 z3 j! u% n6 W
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 |