Răspuns :
x+10x/100=A
A+10A/100=13.31
100A+10A=1331
110A=1331
A=12.1 (pret dupa prima scumpire)
x+10x/100=12.1
100x+10x=1210
110x=1210
x=1210:110
x=11 lei pret initial
11+11b/100=13.31
1100+11b=1331
11b=1331-1100
11b=231
b=231:11
b=21. Deci cu 21%
A+10A/100=13.31
100A+10A=1331
110A=1331
A=12.1 (pret dupa prima scumpire)
x+10x/100=12.1
100x+10x=1210
110x=1210
x=1210:110
x=11 lei pret initial
11+11b/100=13.31
1100+11b=1331
11b=1331-1100
11b=231
b=231:11
b=21. Deci cu 21%
x-pretul initial
10% din x= 10/100 * x= 1/10* x= x/10 -scumpirea
x+x/10= (10x+x)/10= 11x/10-noul pret
10% din 11x/10= 10/100* 11x/10= 1/10* 11x/10 = 11x/100-noua scumpire
11x/10 +11x/100= (110x+11x)/100= 121x/100-pretul dupa cele 2 scumpiri
121x/100=13,31
x=13,31*100/121=
x=1331/121
x=11
b)x/10 + 11x/100= (10x+11x)/100= 21x/100-cele 2 scumpiri
21*11/100= 2,31 -cu cat s-a scumpit
p% din 11=2,31
p/100=2,31/11
p=100*2,31/11= 231/11=21%
10% din x= 10/100 * x= 1/10* x= x/10 -scumpirea
x+x/10= (10x+x)/10= 11x/10-noul pret
10% din 11x/10= 10/100* 11x/10= 1/10* 11x/10 = 11x/100-noua scumpire
11x/10 +11x/100= (110x+11x)/100= 121x/100-pretul dupa cele 2 scumpiri
121x/100=13,31
x=13,31*100/121=
x=1331/121
x=11
b)x/10 + 11x/100= (10x+11x)/100= 21x/100-cele 2 scumpiri
21*11/100= 2,31 -cu cat s-a scumpit
p% din 11=2,31
p/100=2,31/11
p=100*2,31/11= 231/11=21%