Algebra
posted by Cassie on .
The sum of the charges of the quarks in a particles gives the overall charge of the particles. Two up quarks and a down quark make a proton, which has a charge 1. On the other hand, two down quarks and an up quark make a neutron, which has a charge 0. What is the charge of an up quark?
I have no idea how to solve this. I'm assuming that I would make a system of equations, since that is what we're learning about. And what is a quark? Thank you so much!

2 u + d = 1
u + 2 d = 0

2 u + d = 1
2 u + 4 d = 0
 subtract
0 u  3 d = 1
d = 1/3
u 2/3 = 0
u = 2/3
and a quark is something two ups and a down of which make a proton :)