unable to add on to float

unable to add on to float

I have the following code
mFme.Profile.VideoOutput_DataRate = Configs.VideoBitRate;
Configs.VideoBitRate is a public float that is returned from an XML file.
What I would like to be able to do is
mFme.Profile.VideoOutput_DataRate = Configs.VideoBitRate + "\;" +
Configs.VideoBitRate2;
My problem is : I cannot seem to find a proper way to set the variable
like that. It is important that I have semicolon between the two bitrates.
I.E 200;650
Does anyone know the proper way to accomplish this? I am very familiar
with PHP, but not c#.net. What I thought would be a simple task.. is
anything but at the moment.