$29.$ The Brute Force Bandits is a punk rock band planning their

next concert tour. The band has a total of $30$ new songs in

their repertoire.

$($a$)$ How many different set lists of $18$ songs can the band

select to play on the tour? $($Hint: Assume that the order

in which the songs are listed is irrelevant.$)$

$($b$)$ How many different ways are there for the band to

record a CD consisting of $18$ songs chosen from the $30$

new songs? $($Hint: In recording a CD$,$ the order in

which the songs appear on the CD is relevant.$)$ explain the steps pls