x=suma initiala
35x/100 suma cheltuita in prima zi
x-35x/100=(100x-35x)/100=65x/100, suma ramasa dupa prima zi
(65x/100)*(40/100)=(65x/100)*(4/10)=260x/1000=26x/100 suma cheltuita in a doua zi
35x/100=(26x/100)+63
(35x-26x)/100=63
9x/100=63
9x=6300
x=6300/9=700lei=suma initiala