A quick Google search (for a quicker answer instead of waiting on users on BL) would reveal that most substances generally last anywhere from 4-6 hours (a few chemicals aside). Adderall falls under this category. It will last 4-6 hours. I have no idea what a whitegurl is, but if it's the name of an Ecstasy pill press, you shouldn't be mixing Adderall and MDMA, it's very hard on the heart. Smoking weed will intensify Adderall (and ecstasy) and smoking during the comedown can tend to bring back effects, so it could last longer.
I wouldn't advise an Adderall+Ecstasy+Cannabis combination, you're going to be putting your body through a lot. Especially considering you're also mixing it with whatever adulterants were in your Ecstasy pill (usually very nasty stuff). If a "whitegurl" is not Ecstasy, ignore that last part.
You didn't give too much information in your post. This is most probably why nobody is responding to you.
