How do I measure the products of reacted Ethane in L's?

Question

I'm doing a review and this one has me stuck. If someone could break it down for me and give me the answer, and tell me how they got it, you will get many points and much respect. Please and thank you.

-- The complete burning of Ethane, C2H6, produces CO2 and water vapor as its only products. Assume all substances are gases measured at the same temperature and pressure. How many liters of Ethane and Oxygen would produce 7.07 L of CO2?

Answer 1

2 C2H6 + 7 O2 -> 4 CO2 + 6 H2O

So the ratio of C2H6 to CO2 is 1:2 and the ratio of O2 to CO2 is 7:4.

7.07L of CO2 means that there were 3.535 L of C2H6 and that there were 12.3725L of O2

Answer 2

Write the balanced equation. Then volumes of gases are in the same proportion as the numbers of moles in the balanced equation.That's all!