What is the maximum number of branch circuit breakers allowed in a 100 amp panel?

I just spoke with an inspector here in NJ today and according to him pending on what panel(squareD)in this case, it is 24 space but can be 48+. Stating that the breakers allow you to place two branch circuits on one breaker. Didn't make sense to me, being that while in school at my union it was 1 circuit for each breaker. Unless, some tandem breakers are used. Check the breaker and see what its rated for. Hope this helps.