Question

Un elev are o suma de bani. Determinati suma de bani stiind ca dupa ce a cheltuit 1 supra 4 din ea, apoi 1 supra 6 din rest , apoi 1 supra 3 din noul rest si inca 120 lei, i-au ramas 600 de lei.

Answer 1

$x- \frac{x}{4} - \frac{1}{6} X \frac{3x}{4} -120=600$

$x- \frac{x}{4} - \frac{x}{8} -120=600$

(aducem la numitorul comun 8)

$8x-2x-x-960=4800$

$5x=5760$

$x=1152$

Answer 2

x-suma initiala

1/4 in x=  1/4 * x=  x/4 -prima data

x-x/4=  (4x-x)/4=  3x/4 - restul

1/6 din 3x/4=  1/6 * 3x/4= x/8 -a doua oara
 
3x/4- ( x/8+120)=  (6x-x-960)/8=  (5x-960)/8 -noul rest 

1/3 din (5x-960)/8=  1/3 * (5x-960)/8=  (5x-960)/24 -a treia oara 

(5x-960)/8 - (5x-960)/24=  (15x -2880 -5x +960)/24=  (10x -1920)/24 -noul nou rest

(10x-1920)/24= 600

10x -1920= 14400

10x= 14400+1920

10x= 16320

x=1632