A riddle from the supermarket
by hazel from LinuxQuestions.org on (#5790N)
I know more or less how supermarket pricing works. There's a barcode on the packaging and it's linked to a specific price in the central computer. If they want to sell of something off cheap, they put one of those yellow labels on it with a new barcode. When the barcode is scanned, the price comes down the line from the stock record.
Today I wanted to buy some eggs, preferably free-range. They had three stacks of 10-egg boxes for 2 each. I saw at once that was more than I was accustomed to pay; you can usually get half a dozen medium-size free-range eggs for less than a pound. So I decided to buy the caged ones. But just then, a shelf-stacker walked past, pulled off the 2 label from the left-hand stack and said, "Those are only 1.65". So I took a box from that stack. And sure enough, at the checkout, it cost me 1.65.
Now those egg boxes were exactly the same as the boxes on the other two stacks, which were still labelled 2. They all had the same barcode on them. They hadn't been relabelled. How did the computer know they had been reduced in price?
Today I wanted to buy some eggs, preferably free-range. They had three stacks of 10-egg boxes for 2 each. I saw at once that was more than I was accustomed to pay; you can usually get half a dozen medium-size free-range eggs for less than a pound. So I decided to buy the caged ones. But just then, a shelf-stacker walked past, pulled off the 2 label from the left-hand stack and said, "Those are only 1.65". So I took a box from that stack. And sure enough, at the checkout, it cost me 1.65.
Now those egg boxes were exactly the same as the boxes on the other two stacks, which were still labelled 2. They all had the same barcode on them. They hadn't been relabelled. How did the computer know they had been reduced in price?