as this is quite easy, please don't post the answer, but send me PM instead
some dutch guy lost the 5-digit code to open the lock for his bike. however, he remembers some hints which can be used to get to the code:
1) the sum of the fifth and the third digit is 14.
2) the fourth digit is the second digit plus one.
3) the first digit is the double of the second digit, minus one.
4) the sum of the second and the third digit is 10.
5) the sum of all 5 digits is 30.
again, please don't post the answer here, send me PM instead