p=pretul initial al obiectului, p+10p/100=p+p/10=11p/10=pretul dupa prima scumpire, 11p/10+(11p/10)x10/100=11p/10+11p/100=121p/100=pretul dupa a doua scumpire, 121p/100+(121p/100)x15/100=1656
121p/100+(121p/100)x3/20=1656, 121p/100+363p/2000=1656, numitor comun 2000
2420p+363p=3312000, 2783p=3312000 , p=3312000/2783=1190,08 lei