I am assuming you are asking: How dense is the center of a black hole.
Currently, the theoretical mass of a black hole is an infinite value for the sake of physics although it is not known for certain. If blackhole were infinitely dense, then the escape velocity of the blackhole and matter would exceed the speed of light, which is currently impossible with the universally agreed upon theory of Special Relativity created by Einstien; Nothing can reach or exceed the speed of light that isn't already the speed of light. This is due to the properties of matter in relation to velocity. To get an object to move faster, the more energy the energy is required to do so. Also, the heavier an object will become in relation to the area around it, or as we currently know as G-Force. Combined with the velocity you will encounter an issue where you have an object that is so dense and fast that time ceases to exist from a theoretical point of view.
Now to simplify this,
The faster an object goes, the slower it gets. For example, if you were to be shot into space at 99.8% the speed of light and spent 10 years in orbit at the constant speed, it would feel like 10 years to you, and you would have only aged 10 years. If you were to go back to Earth, a 5-year-old would be 80 years old approximately. Meaning 10 years have passed for you while 75 years have passed for people on earth at a velocity of around 1% the speed of light. So when you are going the speed of light, time itself will seemingly stop.
Combined with the task of pushing an object with an increasing mass causes you to need more energy until you reach a point of 99.9% the speed of light, where it will be impossible to make it go any faster.
That being said, I do not believe that Black holes are infinitely dense, but it is impossible to tell at this current time and I would be a fool to guess any number because it can be from 1 to Infinity. It's physically impossible to tell.
So I hope this lil rant is the answer you were looking for,
For right now I will say the Black hole is infinitely dense because there is no number to comprehend its mass.
Tldr: 7 cubic pounds.