Notez cu x-suma initiala
1/4 din 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 =(6x-x)/8= 5x/8 -noul rest
1/3 din 5x/8 +120= 1/3 *5x/8 +120= 5x/24 +120 -a treia oara
5x/8 -(5x/24 +120)= (15x-5x-2880)/24= (10x2880)/24 -noul nou rest
(10x-2880)/24= 600
10x-2880=24*600
10x=14400+2880
10x=17280
x=1728