In a fish tank, there are some goldfish and 5 angelfish. The ratio of the total mass of the angelfish to the total masd of the goldfish is 2 : 7. The total mass of the goldfish is 1.4kg. Find the average mass of one angelfish.

This is a multistep problem that requires more than one step. The first step is finding what 2/7 of 1.4 kg is. To do this we multiply 2/7 by 1.4, which gives us an answer of 0.4 kg for the total mass of angelfish. Now, to find the mass of one angel fish we divide 0.4 (the total mass in kilograms) by 5 (the number of angelfish). This leaves us with a final answer of 0.08. So the average angel fish weighs 0.08 kilograms.