RoR in X amount of hands.

[ShakeZula06]

Let's say I'm bankrolled with 250 BBs, and will play X hands to clear a bonus at a table/site/limit where I have 1.5 BBs/100 hand WR and a SD of 17/100 hands. What formula would I use to calculate my RoR?

I'm experimenting with some bonus whoring and since I've had my money spread around in a few places at no game do I have the recommended 400-500 BBs for limit 6max at any particular room. However since my moneys only on there for a certain amount of hands I figure my RoR is much smaller. Does that sound right?