The Conversion of a into B Has A $\Delta$ G of +13 Kcal/mol, and the Conversion of C into of +13

Essay

The conversion of A into B has a $\Delta$ G of +13 kcal/mol, and the conversion of C into D has a $\Delta$ G of -25 kcal/mol. If the two reactions are coupled through an enzyme, such that A + C goes to B + D, what is the free energy change, and in which direction will the reaction proceed?