Question

The mass of 4.5 cm3 of iron and 8 cm3 of copper is equal to 101.5g. The mass of 3 cm3 of iron is 6.8g greater than the mass of 2 cm3 of copper. Find the density of iron and the density of copper.

Answer 1

Let m be the density of iron
Let M be the density of copper
So, m = M = 101.5 grams

We know that the formula for mass is:
m = d x v
where:
m is mass
d is density
v is volume

the density of iron is calculated by d = m / v, we derived this formula from the mass formula.
So d = 6.8g/ 3.3cm^3 = 2.26 g/cm^3

It was said that the density of iron is more than the density of copper, so 6.8 should be greater than 2xd, it indicates that d is less than 3.4.

Therefore, the density of copper is more likely less than 3.4g/cm^3