How to find productivity

Country B can produce 4 computers or 6 cars. , so Country B must give up 1.5 cars to make a computer. Country A can make 5 computers or 10 cars. , so Country A must give up producing 2 cars to make 1 computer.

Absolute advantage is determined by which country can produce more, regardless of efficiency. Country A can produce more computers than Country B, so it has the absolute advantage in producing computers.