Question

Un elev are o suma de bani. Determinati suma de bani stiind ca dupa ce a cheltuit

¹/₄ din ea , apoi ¹/₆ din rest , apoi ¹/₃ din noul rest si inca 120 lei , i-au mai ramas 600 lei 

Help me !

Answer 1

Notez cu s suma de bani.
$\frac{1}{4} * s = \frac{s}{4}$
rest: s - $\frac{s}{4} = \frac{3*s}{4}$
cheltuie apoi $\frac{1}{6} * \frac{3s}{4} = \frac{s}{8}$
noul rest : s - $\frac{s}{4} - \frac{s}{8} = \frac{5s}{8}$ . $\frac{1}{3} * \frac{5s}{8} = \frac{5s}{24}$

s- $\frac{s}{4} - \frac{s}{8} - \frac{5s}{24} - 120 = 600$

$\frac{24s-6s-3s-5s-120*24}{24} =600$
10s -120 * 24 = 600 *24
s = 1728

Verificare : 1728 : 4 = 432
rest: 1728 - 432 = 1296
1296 : 6 = 216
noul rest : 1728-432-216 = 1080
1080 : 3 = 360
Se mai cheltuie 120 
1728 - 432 - 216 - 360 - 120 =600