Thank you for the opportunity to help you with your question!
we are drawing 3 balls which is represented by i, j, k respectively ,
for the i=1, getting j=1 and k=1 is allowed so
the all three balls can be the first ball b1
so this is with replacement
and the first for loop contains the n size and then the second for loop inside that contains n size and the the third for loop contains n size inside the second for loop and this is the loop that contains the print command. so
the print command will execute n*n*n = n^3 times
so the programme will print n^3 lines
Please let me know if you need any clarification. I'm always happy to answer your questions.