ISI 2011 and 2012 Sample Question

[Zen]

Didn't find the solution anywhere.  Can someone show the steps?



My attempt (Please tell if I am wrong):
I am assuming zero cost of production.
For (i), price of X=3, price of Y=3, net profit to monopolist=12.
For (ii), price of bundle=4, net profit=12.
For (iii), price of X=4, price of Y=4, price of bundle=6, net profit=14.
Thus, (iii) is optimal pricing strategy.

Please help.

[onionknight]

I think your solution is correct.