Answer:
A) 20+0.6
B) Domain is [0, 50] (inclusive)
C) 8.33 litres
Step-by-step explanation:
Assuming there is a 40% acid concentration in a 50-litre container.
The quantity of acid in this container amounts to 40% of 50 litres.
Quantity of acid = 
litres are extracted.
The acid volume removed equals 40% of
litre.
Remaining acid in the container thus becomes = (20 - 40% of
) litre
This is then substituted with pure acid.
Final acid content in the container is therefore = (20 - 40% of
+ 100% of
) litre
Quantity of acid in the final mixture:

Answer A) Final mixture acid content = 20+0.6
Answer B)
cannot exceed 50 litres (the container's initial volume) and must be at least 0 litres.
Thus, the domain is [0, 50] (inclusive)
Answer C)
For the final mixture to contain 50% acid.
The acid volume = 50% of 50 litres = 25 litres
By applying the equation:
