Help with Calculation, if you can??

[wiw4]

Im sure its an easy answer, but have wrecked my brain trying to figure this out, so after a few no-go googles I've decided to see if anyone in here can help. I find an example always helps: Lets say you have a system with a 12% strike rate (SR), to find the odds you need per selection; to break even at level stakes you usually go 1/SR, so 1/0.12 = 8.33 or 7.33/1. Is a lay system the same only you're laying rather than backing or is there a different calculation. Any help appreciated!!

[Datapunter]

Re: Help with Calculation, if you can?? Laying is backing something not to happen, same thing.