the answer is -$97 for sure. . y6 j1 W1 F# j, q/ J( l
Think about it this way TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。( @/ L1 f. |) } [$ [" n
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)5.39.217.76# ~) P; M8 \5 U) r3 d
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 |