I didn’t have a budget or anything so I found it mildly interesting that it turned out an even number.

    • herrcaptain@lemmy.ca
      12·
      9 months ago

      Thanks for making me spend like 30 seconds of my life reviewing someone’s grocery receipt. We’re really starting to stretch the mildy part of mildly interesting, but apparently I’m here for it.

      • wgbirne@feddit.de
        8·
        9 months ago

        This right here is exactly the kind of content that was posted in r/mildlyinteresting when it was new. After the sub went popular the content was way too interesting for my liking.

  • CubbyTustard@reddthat.com
    7·
    9 months ago

    what’s the odds on this? i would imagine a 1% chance but there’s probably some effect of having so many prices end in 9 that makes the cents not really random

    • colourlesspony@pawb.socialOP
      4·
      9 months ago

      I was wondering the same thing. I was trying to buy exactly 10 items because that’s the max they allow at the self check out now. I’m wondering if that increase the odds greatly or something.

      • sqibkw@lemmy.world
        4·
        9 months ago

        Buying 10 items would definitely make this way more likely, because we have a base-10 counting system.

        To simplify the problem, if you look at the cents digit, $0.09×10 items = $0.90. If you look at both cents digits, they were mostly $0.99. $0.99×10 items = $9.90.

        All you’d need in either case there is something to cost $0.10 more to get a nice even number.

  • Deepus@lemm.ee
    0·
    9 months ago

    Am i being stupid…how does 10 numbers ending in 9 end up ending in 0?

    I know it works, ive added it up myself but it shouldn’t work should it?! Am i going crazy?!

    • merc@sh.itjust.works
      1·
      9 months ago

      Ten number ending in 9 is essentially the same as those same ten numbers but ending in zero plus ten nines.

      $1.19 = $1.10 + 0.09

      $1.19 + $1.69 = $1.10 + $1.60 + (2 * 0.09)

      Since there were 10 items, each ending in a 9, that’s the same as 9 times 10, or in this case $0.09 * 10. Every time you multiply by 10 you end up with a zero on the end.

      In a base 10 system multiplying by 10 basically shifts all the digits over by 1 and adds a zero to the end. Whatever was in the 10s spot goes in the 100s spot. Whatever was in the 100s spot goes in the 1000s spot, and so on.

      So, if you buy 10 items with a 9 at the end of their price, you’ll always end up with a zero in the cents spot. If you buy 100 items like that, your total will be in dollars with zero cents.

      What’s more impressive here is that so many of the other digits ended up as zero when there was no pattern. Ten items ending in ‘9’ means that you carry over a ‘9’ to the next column, but to get that to be zero means the sum of all the tens (of cents) digits needed to end up in a 1.

      1 + 6 + 9 + 4 + 9 + 9 + 6 + 6 + 2 + 9 = 61

      And to get to exactly 40, the dollars digits needed to match that 6 plus 1 carried over (1 + 9), so they needed to end in 3 (or to be 33 exactly for the total to be 40):

      1 + 1 + 6 + 5 + 3 + 3 + 5 + 5 + 3 + 1 = 33

      Ignoring the fact that grocery stores suck and price things ending in 9 all the time, it’s a 1/10 shot to get the cents digit to end up as a zero, a 1/10 shot for the hundreds to end up as zero, and 1/10 for the dollars digit to end up as a zero. OP just used up a lifetime of luck for a 1/1000 occurrence.

      To OP: GG Cheese!