Density scales inversely with volume for equal mass Steps:

• Density ρ = mass m / volume V.
• Side of Y is s, so side of X is 2s.
• Volume of Y: V_Y = s³.
• Volume of X: V_X = (2s)³ = 8s³.
• Ratio ρ_X / ρ_Y = (m / V_X) / (m / V_Y) = V_Y / V_X = s³ / 8s³ = 1/8 = 0.125.

Why A is correct:

• Density is mass over volume; with equal mass, larger volume of X (8 times Y's) means ρ_X is 1/8 of ρ_Y.

Why the others are wrong:

• B: Assumes equal densities, ignoring volume difference.
• C: Matches linear scaling (side ratio 2), but density uses cubic scaling.
• D: Inverse ratio, as if comparing Y to X.

Final answer: A