You can give a reputation to the same person only if you have repped 5 persons after that. Having said that, you can give a maximum of 10 reputations per day. Rep power is calculated on the basis of how old a member is in this forum. A person may have only 30 posts, but if he is 4 years old in this forum, his rep power may be 40 or 50. BTW, the exact method of calculating rep power nobody knows besides the admin. I think it increases by one per month or 2 months. Also, the method to calculate it keeps changing from time to time.
The problem with internet quotes is that you can't trust their authenticity.
- Abraham Lincoln
Q: I thought you were done.
James Bond: I am. I just need one more thing.