George Bailey and the Extra-Strength Rogaine
Here's the answer. George takes one pill from the first bottle, two from the second, etc. He ends up with 55 pills, which should weigh 275 grams (55 pills times 5 grams). If they weigh 276 grams, he has one faulty pill, and he knows it's from bottle #1! If they weigh 278 grams, he has three bad pills from bottle #3, etc.
Sadly, he failed to impress his date. (Maybe it had something to do with the Dodge Dart he was driving.)
[ Car Talk Puzzler ]