the answer is -$97 for sure.
* P* ^1 o$ L" F$ B# Y( otvb now,tvbnow,bttvbThink about it this way
u8 P8 P! z# P# STVBNOW 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。1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)tvb now,tvbnow,bttvb$ B; [& q5 h) P+ r7 {
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 |