Answer: 2Liters
Explanation:
The expression used will be :
[tex]M_1V_1+M_2V_2=M_3V_3[/tex]
where,
[tex]M_1[/tex] = concentration of first antifreeze= 60%
[tex]M_2[/tex] = concentration of second antifreeze= 10%
[tex]V_1[/tex] = volume of first antifreeze = x L
[tex]V_2[/tex] = volume of second antifreeze = 8 L
[tex]M_3[/tex] = concentration of final antifreeze solution= 20%
[tex]V_3[/tex] = volume of final antifreeze = (x+8) L
Now put all the given values in the above law, we get the volume of antifreeze added
[tex]60\times x+10\times 8=20\times (x+8)[/tex]
[tex]x=2L[/tex]
Therefore, the volume of 60% antifreeze solution that must be added is 2L