I am working on a resistor lab. I found the resistivity of 5 resistors all made of the same material, a silver-nickel composite. I would like to find the percent silver/nickel of the wire.

Average Resistivity: 4.56e-7

Resistivity of Silver: 1.59e-8

Resistivity of Nickel: 6.99e-8

Here is my equation:

Ω_silver (percent)+ Ω_nickel (100-percent)= Ω_composite

With everything substituted:

[1.59×〖10〗^(-8) ][%]+ [6.99×〖10〗^(-8) ][100-%]= 4.56×〖10〗^(-7)

But this gives me % = 121.

Now I realize that these resistivity values are at 20c and my lab was warmer and that the wire most likely has some other materials in it, but shouldn't I be able to get a reasonable answer?

What am I doing incorrectly?

P.S. Sorry for the simplicity of this question in comparison to all the other questions here. This was the first place that showed up on Google. Thanks for your help.