Question

O persoana are o suma S de bani. In prima zi cheltuie 30% din suma S, a doua zi cheltuie 40% din suma S, iar a treia zi cheltuies 1/4 din suma S. Persoanei ii raman 100 de lei dupa cele 3 zile. Determinati valoarea sumei S.

Answer 1

I zi a cheltuit: 30s/100=3s/10
II zi: 40s/100=4s/10
III zi:s/4
s-3s/10-4s/10-s/4=100
(40s-12s-16s-10s)/40=100
2s=100x40
s=4000/2
s=2000 lei