Mental arithmetic
This should be a simple problem - purchase four books at £7.99 each. These books are all in a 'Buy one get one half price offer'. An extra 20% off is available via a card. How much should it cost?
In quick terms it's £8 times 4, but with two at half price (equating to one full price book) it's really £8 times 3 or £24. Shift the decimal place for 10% to make £2.40. Times by 2 to make 20% £4.80. £24-£4.80 = £20-£0.80= £19.20 roughly speaking.
I thought £22.38 was a bit off. I paid the money walked away doing the sums in my head and coming to the answer above. Went back in and pointed this out. Taps on a calculator later and I was right. It turns out the till had only halved the price of one book.
Can't trust tills.
2 comments:
True fact: Every computer error is, in fact, a human error. ;-)
Indeed. In this instance it seemed that three books from the shelves and one book from the bestseller list resulted in that one book not registering in the offer.
Given this was a store-wide offer one would think it easy to programme - Is it a book? Count the books and divide by two rounding down. Sort the books in price order and halve the number calculated.
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