For this problem, we need to list the percentages of ALL of the gasses. The answers below are for Nitrogen only, but in the real test you will need to list them all.
This problem is dealing with a ratio of gasses, which we will then turn into a percentage.
First we will calculate the total number of parts, we will do this by adding up the number of parts or each gas.
Then we can calculate the ratio of each gas by dividing the number of parts for each gas by the total number of parts: