The following picture is where the question comes from, just google this document if u need it.

7. The ethyl synthesis, shown below, is another synthesis by which ibuprofen is manufactured. Calculate the percentage atom economy for this reaction. H.C2 CHE H HEC HC 0 AI HO EN Cyo CI HC2 AICI: HC CH CH, H2C CHE CH3 o HO H OH OH HT, HO H/Pd H2C CHE H2C CH3 The BHC Company Synthesis of Ibuprofen A Greener Synthesis of Ibuprofen Which Creates Less Waste and Fewer Byproducts