There are two types of jar In the 1st jar the ratio of copper and aluminium is 1 2 and in the 2nd Ja...........

There are two types of jar. In the 1st jar the ratio of copper and aluminium is 1:2 and in the 2nd Jar is 1: 4. In what ratio these two jar should be mix to make 3rd jar In which the ratio of copper & aluminium become 1:3?