The element tin has three densities depending on various factors. Grey tin has a density of 5.77, ordinary tin has a density of 7.28, and white tin has a gravity of 7.365.
Copper has a density of 8.92.
Since the sample density is 8.59, it is clear that most of the sample is made of copper.
To answer this question, I will use the density of ordinary tin.
let x = the percentage of copper; then 1 - x = percentage of tin
then 8.92x + (1 - x)7.28 = 8.59
expanding, 8.92x + 7.28 - 7.28x = 8.59
combining, 1.34x = 1.31
x = 0.9776; times 100% = 97.76% copper
then 1 - x = 0.0224; times 100% = 2.24% tin