The answer is 0.34. I need full correct working step for it. I am uploading twice coz of wrong answer pereviously. so plz provide correct one

The engine uses kerosene as fuel. Kerosene is a blend of several hydrocarbons. Its average chemical composition can be written as C13H25. 2k) Knowing that atmospheric air consists of 21% oxygen and 79% nitrogen (by volume) and using the molecular weights given in the table, calculate the equivalence ratio