Mathematically combine the three given reactions so that they sum to give a balanced chemical equation describing the production of propane, C3H8(g), from its elements, C(s,graphite) and H2(g). Show your intermediate steps. For example, if you must reverse reaction (c), write the reverse in the appropriate format; if you multiply reaction (a) by 2, write the updated equation. Make sure to enter the overall balanced equation at the bottom.

a. C3H8(g)+ 5O2(g) → 3CO2(g) + 4H2O(l)
b. C(s)+ O2(g) → CO2(g)
c. H2(g)+ 1/2O2→ H2O(l)