The alloy contains copper and silver in a ratio of 8: 1 by weight. What will be the weight of a piece of this alloy

The alloy contains copper and silver in a ratio of 8: 1 by weight. What will be the weight of a piece of this alloy in air and in water if its volume is 10 cm3?

Density of copper: 8900kg / m3 Density of silver: 10500kg / m3
You can calculate the pushing force using the formula:
F = P (density of liquid or gas) * g * V
You will also need gravity:
F = mg
The first step is to find the density of the alloy:
P = m: v = (8 + 1): (8 / (copper density) + 1 / (silver density)) = 9: (8/8900 + 1/10500) = ~ 9071.675 kg / m3
F = mg = V * P * g = 0.00001m3 * 9071.675 kg / m3 * 9.8066 = ~ 0.89 N
F (expulsion force in air) = P (at room) * 9.8066 * 0.00001m3 = 1.2kg / m3 * 9.8066 * 0.00001m3 = 0.0001 N
P = 0.89 N – 0.0001 N = 0.8899 N – weight in air
Ejection force in water:
F = 1000kg / m3 * 9.8066 * 0.00001m3 = 0.098 N
P = 0.89 – 0.098 = 0.792 N – weight in water