Sounds like a homework problem to me. Here's a hint:
(1) Calculate the net cost of 150 shares (position cost plus brokerage fee)
(2) Calculate the net cost of 100 shares
(3) Determine your cash outlay for 100 shares (excluding margin amount)
(4) Calculate net sale price of 100 shares (proceeds from position less plus brokerage fee)
(5) Income is sale proceeds less cost of that position
(6) Yield is profit over cost (excluding margin component)
If that's not clear, sorry but I can't do it all. Now it's your turn.