Pf = pretul final
Pi = pretul initial
Pr = procent la suta
Pf = Pi + Pr% x Pi
Pf1 = 10/10 + 5/100 x 10/10 = 10/10 + 50/100 = 105/100 = 21/20
Pf2 = 21/20 + 4/100 x 21/20 = 21/20 + 84/2000 = 273/250 (dupa simplificari)
Inlocuim in formula:
1092/1 = 273/250 = (1092 x 250)/273 = 1000
verificare:
1000 x 5% = 50, 1000 + 50 = 1050
1050 x 4% = 42, 1050 + 42 = 1092
Multa bafta