the answer is -$97 for sure.
1 h) o; y: R: g1 SThink about it this way 5 \# E; ]* _ ]+ ~+ l n
1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
/ z6 w8 _, ^$ tTVBNOW 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 |