The iPad passcode and the restrictions passcode could be the same, but if you did not set the restrictions passcode, then you obviously have a problem. Unfortunately, if the restrictions passcode is not working you have to restore the iPad to factory settings - meaning erasing and restoring as new.
If you have a backup that doesn't contain the passcode, you should be able to restore from that backup and then that would erase the settings passcode and you could get back into the settings. However, in order to restore from a backup now in iOS 7, you have to turn off Find my iPhone in the settings first. If you cant get into the settings, you cant turn Find my iPhone off.