I'm glad Day One is over! :)

Today's topic is on "Influencing Others"... and the facilitator gave us a brain teaser that killed a couple of our brain cells. A simple arithmetic question that took the group a while to come to a consensus. Here goes the role play ~

Cast: Linda (Shop keeper 1), John (Shop keeper 2) & Carol (Buyer)

Carol has always wanted to buy a photo frame. After much contemplation, she went down to a street, where there are 2 shops that sell a varieties of photo frames. First, she stepped into Shop 1 owned by Linda. After much recommendations and promotions by Linda, Carol has almost decided to buy a photo frame selling at $78 (no discount). But she decided to pop by Shop 2 first before making a decision. Then, she went into Shop 2 owned by John. Unfortunately, none of the photo frames caught her eyes. Thus she went back to Shop 1 to buy the photo frame at $78. Carol handed $100 to Linda, but the latter did not have the change. Hence Linda went to John to small change the 100 bucks, after which passed the change of $22 to Carol. After 10 minutes, John realised that the 100 bucks is a fake note. John went back to Linda and asked for a real note. Without much choice, Linda exchanged a real note with John.
Question: How much did Linda lose in the deal?