How Many Liters (L) of A $40 \%$ Alcohol Solution Must Be Mixed With

Multiple Choice

How many liters (L) of a $40 \%$ alcohol solution must be mixed with $60 \mathrm{~L}$ of a $60 \%$ solution to get a $50 \%$ solution?

A) $120 \mathrm{~L}$
B) $60 \mathrm{~L}$
C) $12 \mathrm{~L}$
D) $6 \mathrm{~L}$