Brain Teasers
No Zeros
Can you find a five digit number which has no zeros and no digit is repeated, and where:
The first digit is a prime number.
The second digit is the fifth digit minus the first digit.
The third digit is twice the first digit.
The fourth digit is the third digit plus three.
The fifth digit is the difference between the first digit and the fourth digit.
The first digit is a prime number.
The second digit is the fifth digit minus the first digit.
The third digit is twice the first digit.
The fourth digit is the third digit plus three.
The fifth digit is the difference between the first digit and the fourth digit.
Answer
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Comments
Excellent!
i enjoyed it! the key is working back to the second digit... i guess that could be a hint =)
May 23, 2002
Thank you - that was a fun one!
fun, but easy,
it only took about 1 minute to figure out, but i enjoy problems such as these. You just use simple algebra to figure it out starting with the first number. You would do abcde(each letter to represent a number) and then put each into an equation. Again this is very simple, like 6th grade algebra.
Good Job... took some time and i do hate ppl that brag.. ya one minute my ass..
I agree with rohddawg, it took me 5 mins, no-one can do it in 1 min! I h8 braggers!
could 13254 work as well or is one not considered prime? Either way it was a fun one!
thanks to everyone who thought it was good!!
To dumbdumb_smarts: yoiu are right about the number 1 not being prime. As a technicial matter, the smallest prime number is 2, and therefore the lead digit cannot be 1. good point though.
I'm not very good at maths ones, but it took me about 10 minutes. It was a good one though.
that was easy
I just want to know how you got the inspiration to make this riddle!?
Anyway brilliant riddle, its going to my math teacher definitly!
Anyway brilliant riddle, its going to my math teacher definitly!
lol for whoever said one minute was impossible, it took me about 10 seconds.
2 isn't a prime number. I'm going to 7th grade and we learned about these since 4th grade.
13254 is also an answer to that teaser...I'm pretty sure 1 is considered a prime number
That was a nice one. Yeah, I choked, I misread a direction, but it was still good. 1 and 2 are both prime.
yup. i took less than a minute but more than 10secs. maybe half a minute or so. its very simple. the first no., i took as A, could either be 2,3,5,7 but the C countered the last two cus twice of 5 was 10 and thats two digits. A and B, C and E, are 3 and 6. repeated. left me with only two digits (2,3) to solve from.
2 is definitely prime, whoever who said is isn't. But 1 isn't. It old books, authors wrote that it was but most of today's textbooks states that 1 is neither prime nor composite. www.utm.edu 's list of prime numbers excludes 1. A prime number is defined as any number which can only be divided by its own and 1. 2's factors are 2 and 1 so its a prime number. 1 can be divided by 1 and its own, which is 1. Prime numbers have two factors and 1 only has 1. errr... something like that
Yep. Quite sure 1 isn't prime and 2 is. To be prime you have to have 2 factors. to be composite you have to have more than 2. 1 fits in neither. about the problem, people weren't bragging they were just proud of an accomplishment i guess. fun and easy problem. good gap for the really lengthy ones.
i enjoyed this one. it was just a nice refresher.
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