Question

O persoana are o suma de bani. In prima zi a cheltuit 2/7 din suma,a doua zi 1/4 din rest,a treia zi 2/5 din noul rest iar a patra zi 5/9 din noul rest.aflati intreaga suma stiind ca i-au ramas 6 lei

Answer 1

1)2x/7   ;    x-25/7 =7x/7-2x/7 =5x/7   rest
2)1/4 *5x/7 =5x/28     ;    5x/7-5x/28 =20x/28-5x/28 =15x /28     rest
3)2/5 *15x/25 =3x/14   ;   15x/20 -3x/14 =15x/28-6x/28 =9x/28  rest
4)5/9 *9x/28 =5x/28
5)  6 lei

2x/7+5x/28+3x/14+5x/28 +6 = x   numitor 28
8x+5x+6x+5x+168 =28x
28x-8x-5x+6x+5x =168
4x =168 
x = 42 km