Question

Un elev are o suma de bani pe care o cheltuie in trei zile. In prima zi cheltuie jumatate plus inca 12 lei, in a doua zi o treime din rest plus 10 lei iar in a treia zi restul de 12 lei. ce suma are elevul ?

Answer 1

x=suma
x/2+12=ziua1
x-(x/2+12)=x/2-12=rest
(x/2-12)×1/3+10=x/6-4+10=x/6+6=ziua 2
x/2+12+x/6+6+12=x
x/2+x/6+30=x
3x+x+180=6x
2x=180
x=180:2=90 lei