Răspuns:
fie x suma de bani
prima data s a cheltuit
0,2*=1/5*x
rest=4/5*x
5/5*x=x
0 1(6)=(16-1)/90=15/90=1/6
a doua oara
1/6*4/5*x=2/15*x
total cheltuit
(1/5+2/15)*x=(5/15)*x=1/3*x
rest=2/3*x=28
x=28*3/2=42 lei inițial
s a cheltuit a doua oara
2/15*42=84/15=28/5=5,6 lei