ziua 1 30%=3/10
ziua 2 40%=4/10
ziua 3 1/4
a) in ziua 2 cheltuieste cel mai mult
3/10=6/20
4/10=8/20
1/4=5/20
8/20>5/20>6/20
b)
1-3/10-4/10-1/4=1-7/10-1/4=(20-14-5)/20=1/20
s=suma initiala
s/20=600 lei
s=12000 lei
12000 ×30%=3600 lei ziua 1
12000 ×40%=4800 lei ziua 2
12000 ×1/4=3000 lei ziua 3