The volume of the hollow aluminum ball is 30cm3, the mass is 27g, and the total mass is 43g after filling with a certain liquid?

The volume of the hollow aluminum ball is 30cm3, the mass is 27g, and the total mass is 43g after filling with a certain liquid?

(1) 7 × 103kg / m3 = 2.7g/cm3, from ρ = MV, the volume of 27g aluminum: V aluminum = m ρ aluminum = 27g2.7g/cm3 = 10cm3, the volume of hollow part: V air = V ball-v aluminum = 30cm3-10cm3 = 20cm3; (2) the mass of liquid filled: m liquid = m total '- M = 43g-27g = 16g, the volume of liquid:

The volume of a metal ball made of iron lead alloy is 5 cubic decimeters, in which the volume of iron accounts for 30% of the total volume. How to find out if the metal ball is made of iron lead alloy?
Answer quickly

Mass of iron M = 5 * 10 ^ - 3 * 30% * 7.8 * 10 ^ 3 = 5.67kg
Mass of lead M = 5 * 10 ^ - 3 * (1-30%) * 11.3 * 10 ^ 3 = 39.55kg
Density p = (5.67 + 39.55) / (5 * 10 ^ - 3) = 9.044 * 10 ^ 3kg / m3

The volume of a metal ball made of iron lead alloy is 5 decimeters ^ 3. In fact, the volume of iron accounts for 30% of the total volume. What is the density of the metal ball
The volume of a metal ball made of iron lead alloy is 5 decimeters ^ 3. In fact, the volume of iron accounts for 30% of the total volume. What is the density of the metal ball? (P iron = 7.8 * 10 ^ 3kg / m ^ 3, P lead = 11.3 * 10 ^ 3kg / m ^ 3)

7.8×30％＋11.3×70％＝10.25