Răspuns :
288...........120%
x................100%
x=288*100:120= 240
240...........80%
x..................100%
x=240*100:80= 300
verificare:
300.........100%
x...............80%
x=240
240............100%
x.................120%
x=288
x................100%
x=288*100:120= 240
240...........80%
x..................100%
x=240*100:80= 300
verificare:
300.........100%
x...............80%
x=240
240............100%
x.................120%
x=288
X-pretul initial . x-20/100×X=X-X/5=4X/5 pretul dupa reducere. 4X/5+20/100×4X/5=4X/5+4X/25=24X/25 pretul dupa scumpire. 24X/25=288 => x=288×25/24=12×25=300 lei pretul initial