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Price tags · Puzzle #15 · Wednesday, October 14

Price tags: the answers

Four questions, each with one true number. Here they are with their answers, how to reason each one out, and where the number comes from. Play today's Price tags.

  1. 1. A year of private college tuition: What was the average published tuition and fees for one year at a private nonprofit four-year US college in 2025-26?

    Photo: Daderot, Public domain
    Measured by
    College Board, Trends in College Pricing
    Public four-year, in-state
    $11,950
    Excludes
    Room and board

    The answer: about $45,000. That sticker price rose $1,750 (4.0%) from the year before, before financial aid.

    Napkin math
    1. $12ka year at a public college
    2. ×3times as much at a private one

    ≈$36k

    Source: College Board, Trends in College Pricing: Highlights

  2. 2. A day at Tractor Supply: How much did one Tractor Supply store sell on an average day in 2025?

    Sells
    Feed, pet food, fencing, tools and work clothes

    The answer: about $16,000. Tractor Supply's 2,602 stores include 207 Petsense pet shops.

    Napkin math
    1. 300customers a day
    2. ×$50a purchase

    ≈$15k

    Source: Tractor Supply Company (SEC Form 10-K), Tractor Supply Form 10-K for fiscal year 2025

  3. 3. Sealed 2007 4GB iPhone: What did a factory-sealed, first-release 4GB Apple iPhone from 2007 sell for at LCG Auctions in July 2023?

    Photo: Andrew from London, UK, CC BY-SA 2.0
    What
    An unopened first-generation 4GB iPhone, discontinued two months after launch
    Original price
    $599
    Sold
    LCG Auctions, July 2023, price includes buyer's premium

    The answer: $190,373. It sold for nearly 400 times its original price, far above its $50,000–$100,000 estimate.

    Napkin math: It cost $599 new; if collectors pay a few hundred times the original price for a pristine 'holy grail', you land in the low six figures.

    Source: BBC News, Apple iPhone from 2007 sells for $190,000 at auction

  4. 4. Minecraft (Mojang): How much did Microsoft pay to buy Mojang, the maker of Minecraft, in 2014?

    Bought by
    Microsoft, September 2014
    PC downloads
    More than 100 million since 2009
    Xbox 360 play
    More than 2 billion hours in two years

    The answer: $2.5 billion. Microsoft said it expected the $2.5 billion deal to break even in its first fiscal year.

    Napkin math
    1. 100Mcopies downloaded on PC
    2. ×$25a copy

    ≈$2.5B

    Source: Microsoft News, Minecraft to join Microsoft

All of puzzle #15 · The archive