There really isn't a good answer anyone can give. It depends on a lot of things (specifically your staff, standards, what you did pass, how badly you failed, did you meet the thresholds, did you fail more then one test, etc).
I failed the push ups because of my form during the test, but I passed everything else. They let me stay on the platoon and I re-test with everyone else week 8, but I've worked on my form so I won't lose counts for not going low enough down.
The way it usually works is you do the CF Express and then whoever fails can redo it a few days later. After that they decide who stays and who goes. I know the beep test is paramount. My understanding is that you absolutely need to pass that. If you pass that along with two other things you should be alright so long as you meet the minimum threshold on that one you failed. We had a girl pass everything but she couldn't do a single pushup... She didn't stay (they sent her straight home). But we had a girl who was only one or two away from the standard to pass and they kept her around.
They had us work with the PSP staff on our form and stuff. I did 9 the first time (I lost way too many on bad form), but the last time I did a re-test with the PSP I had 22 (wasn't official but he had been working with us and wanted to see how we did).
I was also told that it depends on the demand for your trade too.
Eh, there's so many variables and I can't cover them all. Just pass the CF Express. Just work on the run and the pushups. You get those to where they need to be and the situps and grip test should be nothing to worry about.
Also... for anyone about to go to BMQ... Get a good grip on the grip test. It has a tendency to slip if you have a bad grip on it and it really lowers the results you get from the squeeze. I did really bad on my first squeeze haha.
edit: Fatalize is pretty much right. My staff were putting the fear of god into us too.