An Ancient Number System
You have been asked to consult on a recently discovered ancient number system. So far, archaeologists have found examples of some symbols associated with expressing quantities. These symbols are ▲, ►, and ◄.
With that information, they have been able to link combinations of these symbols to certain quantities. Their results are in the table above.
Recently, they have found combinations of these symbols referencing two unknown quantities: ►◄▲ and ▲►◄.
What is the sum of the two unknown quantities above?