Please help me with 14 a), b) and c)

Book: Applied combinatorics by Fred Roberts 1st edition

14. (a) A computer center has 9 different programs to run. Four of them use the language ALOod and 5 use the language BASIC. The ALGOL programs are considered indistinguishabie so are the BASIC programs. Find the number of possible orders for running t (i) there are no restrictions; (ii) the ALGOL programs must be run consecutively (iii) the ALGOL be r L programs must be run consecutively and the BASIC programs must be run consecutively; (iv) the languages must alternate. (b) Suppose that the cost of switching from an ALGOL configuration to a BASIC configur- ation is 10 units, the cost of switching from a BASIC configuration to an ALGOL configur- ation is 5 units, and there is no cost to switch from ALGOL to ALGOL or BASIC to BASIC. What is the most efficient (least cost) ordering in which to run the programs? (c) Repeat part (a) if the ALGOL programs are all distinguishable from each other and so are the BASIC programs