Answer: 36 ways
Explanation:
This is probability with replacement
Each of them want to choose a marble randomly from a jar containing nine marbles
The number of ways these four people can choose will be
4( 9 combination 1) that is
4( 9C1) = 4[9!/(9-1)! 1!]
= 4[9!/8!]
= 4(9)
= 36 ways