the answer is -$97 for sure.
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1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
: p; ~7 r' D9 E+ S- a& _- JTVBNOW 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。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 |