In this example, the word "business" does not mean "a company." "Business" is being used to mean something similar to work or tasks you need to complete that are part of a job. Someone might use this when he or she is going to a meeting to negotiate a contract. "I need to go now. I have some important business waiting."

"Business" here is uncountable, like "milk" or "love", so you can't ask "how many".