Statistics questions urgent!!

1) a lecture hall has 1000 seats. For a public lecture 1300 tickets have to be issued to those people who are interested to attend. From past records, about 73% of those who have tickets would not actually turn up.
(a) Formulate a binomial formula to find the probability that it will not be able to accommodate all turn-ups.( you do not have to solve for the answer.)
(b) Find the answer by normal approximation.

2) give a brief interpretation for the term: " a 99% confidence interval estimate of the population mean".

I want the steps and answer .please help me!!!