The original question is unclear: the volume ratio of oxygen and nitrogen in the air is 2 1:78: 1, so how many cubic meters of oxygen and nitrogen are there in 660 cubic meters of air? It is easy for students to do such math problems.

2 1+78+ 1= 100

Every 100 part of air contains 2 1 part of oxygen and 78 parts of nitrogen.

That is, oxygen accounts for 2 1% and nitrogen accounts for 78% in the air.

Oxygen content: 660x2 1% = 138.6 (m3).

Nitrogen: 660x78% = 5 14.8 m3.