Question

Cells use the hydrolysis of adenosine triphosphate (aTP) as a source of energy. This reaction can be written as, ATP(aq) + H2O(l) --> ADP(aq) + H2PO4-(aq), wehre ADP represents adenosine diphosphate. For this reaction, Delta Grxn = -30.5KJ/mol. If all the free energy from the metabolism of glucose, C6H12O6(s) + 6O2(g) --> 6CO2(g) + 6H2O(l), goes into the conversion of ADP to ATP, how many ATP molecules can be produced for each mole of glucose?

I solved for DGrxn for the glucose reaction and got -2872KJ/mol. I don't know how to figure out the number of ATP. Please help.