What is the formula for calculating the density of a composite material?

[joemte]

Homework Statement

A composite material of silicon carbide-filled borosilicate glass is designed with a mixture of 30% of silicon carbide by weight. Given the densities of the consituent materials below:

Silicon carbide = 3.2g cm^-3 (Young's modulus 406 GPa)
Borosilicate glass = 2.23g cm^-3 (Young's modulus 63.7 GPa)

Relevant Equations

None

Does anyone have an equation for the resultant density of the composite materials? Having a look around the internet and I can't find anything, there was this one website that gave me a step-by-step but the answers did not match (sciencing.com)

 

[BvU]

Hi,

Your problem lies with

Homework Equations: None

Forget about the Young modulus and add 30 kg of the one to 70kg of the other in a symbolic expression