the answer is -$97 for sure.
& G( q9 Y y& @) [+ x3 HThink about it this way
3 k$ h) V* }) z9 ^* J6 xtvb now,tvbnow,bttvb1) if the 100 bucks is not a fake one, the store owner will gain $3 ($21-$18)
, g* Z L* T' A- _6 z2) 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 |