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As someone who takes pride in having solved the first 100 problems of project Euler, I am slightly ashamed to admit that I probably spent as much time as your d
by bjoli 9y ago
As someone who takes pride in having solved the first 100 problems of project Euler, I am slightly ashamed to admit that I probably spent as much time as your daughter to solve that.
I got stuck thinking in integers, and quite quickly left the exercise as an oversight in writing the post (since X + y = even, X - y = odd is impossible for integers)
3 seconds into the first coffee of the day the realisation of my stupidity hit me in the face.
- mixmastamyk 9y agoIt's impossible until it's easy, like any good trick question.
- LolWolf 9y agoI mean, is there any other solution? There are certainly no integral solutions to the problem, but there is a unique (rational) solution. I feel like I’m missing something entirely, though...
- Sharlin 9y agoI was also stuck thinking in integers for a few seconds, perhaps because of the context. But yeah, a 10-year-old would already know about fractions.
- endeavour 9y agoI also mentally started thinking about integral solutions. I wonder if it's also because of the variable names... a,b,c tend to be used to represent integers (e.g. Fermat's Last Theorem, Euclid's algorithm etc). x and y are more commmonly used to represent real numbers.
- dzdt 9y agoRandom aside: once in high school I took a math puzzle test. The only problem I skipped was because they asked for "integral solutions." I knew the word "integral" only as belonging to calculus, about which I knew nearly nothing at the time. If I had realized in context it just meant "integer" I could have done it!
- intrasight 9y agoThey did make it a tricky question!
- intrasight 9y agoThanks for pointing that out. I'll use X and Y next time I share this story. Of course my daughter wouldn't have known at the time about the distinction, and neither did I - it having been too long since doing algebra ;)
- bpizzi 9y agoFor the posterity: {a+b=10;a-b=1} translates to {a+b=10;a=b +1}, thus the first equation is ((b+1)+b=10) giving (b=4.5), and from there we get (a=5.5).
- LolWolf 9y agoAnother fun way: add the two equations to get 2A=11 and subtract to get 2B=9.