17 again?
1. Find a six digit number that has a 1 and a 7 in it. Call it A
2. Reverse the digits, Call it B
3. Divide A by B and the result is 17 (rounded to two decimals)
What is A?
2. Reverse the digits, Call it B
3. Divide A by B and the result is 17 (rounded to two decimals)
What is A?
posted by Ragknot at
7:38 PM
13 Comments:
This post has been removed by the author.
461720 is the only number that does it.
How on earth did you come up with that one Ragknot?
Great answer,
How did I come up with the question?
After a couple of very easy questions about 17, and one about swapping the end digit with the first, I thought about making a more thoughtful question about 17.
I wanted to devise a simple puzzle that could only be solved by simple brute force.
Did find any math tools that would help?
1. there are 184,562 six digit numbers that have a 1 and a 7.
2. Since A/B = 17 then A must end with a zero, so A can be more than 10 times B.
3. Only 13,696 six digit number have a 1 and a 7 and ends with 0.
4. Only 372 of these give A/B between 16 and 18.
5. 40 of these give A/B between 16.9 and 17.1
6. One gives A/B = 16.997
Hi Ragknot. I'm still impressed that you came up with it. Haven't tried to see if you were just a jammy git that 17 worked so nicely.
Of course, I used my new toy, Mathematica, to help. There were about another 6 numbers that just failed to make the 2DP. Greetz
ALthough I normally prefer the ones that are deducible with logic alone, it was quite good fun writing a proggy to do it.
you need to use 461720
That's awesome. I used excel to crunch the numbers. Here's the file I used, no VBA required.
http://jump.fm/DMEHG
It is 17 duh
This post has been removed by the author.
This post has been removed by the author.
Anonymous, I'll duh your duh twice. 17 isn't a 6 digit number, 17/71 is not 17 to 2 DP, but otherwise stunningly clever.
Anonymous you should learn to read before you write.
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