x-pretul costumului de haine
I reducere: x-5x/100=x-x/20=(20x-x)/20=19x/20
II reducere: 19x/20-(15/100)·19x/20=19x/20-57x/400=(19x·20-57x)/400=323x/400
323x/400=129200
x=129200·400/323=160000 lei
verificare
I reducere:160.000·5/100=8000 lei a fost reducerea
160.000 lei-8000 lei=152.000 lei pretul dupa I reducere
II reducere: 152.000·15/100=22800 lei a doua reducere
152.000 lei-22.800 lei=129200 lei