The volume of the agar cube remaining is 729 cubic mm
Step-by-step explanation:
Side of the agar cube= 12mm
Side of the agar cube after penetration= 12-1.5-1.5
= 9mm
The orange dye penetrated 1.5mm each side so the side of the agar cube is 9 mm
Volume = a x a x a
= 9 x 9 x 9
= 729 cubic mm