[tex] m_{Fe}+ m_{Al} =25 \ kg[/tex]
[tex] \dfrac{ m_{Fe}}{ m_{Al} }= \dfrac{1}{4} [/tex]
Deci:
[tex]m_{Al}=4*m_{Fe} [/tex]
Inlocuim in prima relatie si obtinem masa fierului:
[tex]m_{Fe}+4*m_{Fe}=25\ kg[/tex]
[tex]5*m_{Fe}=25 \ kg[/tex]
[tex]m_{Fe}=5 kg[/tex]
Aflam si masa aluminiului:
[tex]m_{Al}=4*5=20\ kg[/tex]
Verificare:
[tex]5 \ kg+20 \ kg=25 \ kg \ADEVARAT[/tex]
[tex] \dfrac{5 \ kg}{20 \ kg}= \dfrac{1}{4} \ ADEVARAT[/tex]