Răspuns:
Explicație pas cu pas:
Notam cu x suma totala de bani
[tex]Prima ^{ } zi \\\\40:100*x =\frac{2x}{5}[/tex]
restul după ce a cheltuit in prima zi
[tex]x-\frac{2x}{5} = \frac{5x-2x}{5} = \frac{3x}{5}[/tex]
[tex]II ^{ ^{} } zi\\ \\\frac{60}{100}*\frac{3x}{5} = \frac{3}{5} * \frac{3x}{5} =\frac{9x}{25}[/tex]
[tex]III ^{} {} zi \\\\\frac{2x}{5}-72= \frac{2x-360}{5}[/tex]
adunam cat a cheltuit in fiecare zi
[tex]\frac{2x}{5} +\frac{9x}{25} +\frac{2x-360}{5} = x \\ \\10x+9x+10x-1800=25x\\\\29x-1800=25x\\\\29x-25x=1800\\\\4x=1800\\\\x = 450 lei[/tex]
suma cheltuita in prima zi: [tex]\frac{2*450}{5} = 180[/tex] lei
suma cheltuita in a doua zi: [tex]\frac{9 * 450}{25} = \frac{4050}{25} = 162 lei\\[/tex]
suma cheltuita in a treia zi: 180 - 72 = 108 lei
