a)x-pretul initial
I majorare: x+20x/100=x+x/5=(5x+x)/5=6x/5
II majorare: 6x/5+(6x/5)·20/100=6x/5+6x/25=(30x+6x)/25=36x/25
36x/25=432
x=(432·25)/36
x=300 lei pretul initial
b) 300·p/100=432
p=432/3
p=144
deci cu 44% ar trebui marit pretul o singura data
verificare
300+300x44%=432
300+132=432