the answer is -$97 for sure. TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。9 c% Z$ U6 ]6 W6 t$ h e& e
Think about it this way
. l# C! \, o) s5.39.217.77:88981) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)- ?& s$ V5 P0 |# a& E( w: }. x
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 |