When acetonne, C3H6O, is oxidized via cumbustion, the following reaction can be envisioned. Balance this reaction and determine the total of the coefficient when added together.

Write down the equation for the reaction taking place. Remember that organic compounds with carbon, hydrogen and oxygen give only carbon dioxide and water upon complete combustion.

And I'm not sure what you mean by "the total of the coefficient when added together"... I have never ever seen that before.