Epic systems Interview questions

Epic systems Interview questions 1)Write algorithm to return change in denominations of 10$, 5$, 1$, 25 cents, 10 cents etc?
2)Explain algorithm for Replace all single occurrences of "a" with "the"?
3)Write Program to find no. of days between Jan1st and entered date?
4)Given a string.Replace the words whose lengt>=4 and is even,with a space between the two equal halves of the word.consider only alphabets for finding the eveness of the word

I/P "A person can't walk in this street"
O/P "A per son ca n't wa lk in th is stre et"
5)if a clock looses 2 secs per day, how much time will it loose in 2 days ?
6)What are callbacks?
7)What is static functions?
8)What are the concepts you know in oops explain?
9)In how many ways cube can be painted using three different colours?