x=suma initiala
35x/100+3= 1 zi
3x/10+4 = a 2-a zi
x/4+6= a 3-a zi
35x/100+3+3x/10+4+x/4+6+373=x
x-35x/100-3x/10-x/4=386
100x-35x-30x-25x=38600
10x=38600
x=3860 lei suma initiala
1 zi = 3860x35%+3=1354 lei
a 2-a zi = 3860x3/10+4=1162 lei
a 3-a zi = 3860:4+6=971 lei
in a 3-a zi cheltuie cel mai putin