Question

Matei a cheltuit sambata dupa amiaza doua cincimi din suma pe care o avea dimineata.Duminica,dupa ce a mai cheltuit inca 13 lei,Matei mai are 8 lei din suma initiala.Determinati suma pe care a avut-o Matei sambata dimineata.

Answer 1

8+13=21
1-2/5=3/5
21:3*5=7*5=35(lei)-avea Matei

Answer 2

cat a cheltuit sambata
x-suma initiala
x-2/5·x=x-2x/5=(5x-2x)/5=3x/5
cat a cheltuit duminica?
3x/5-13=(3x-13·5)/5=(3x-65)/5
care este suma initiala
(3x-65)/5=8
3x-65=8·5
3x=40+65
x=105/3
x=35 lei suma initiala

verificare
sambata a cheltuit: 35x2/5=14 lei
suma ramasa:35-14=21 lei
sum ramasa duminica: 21-13=8 lei