The multiple of 4 from 4 to 100

What can you determine about the solutions of this system

Aquadratic equation in standard from is written ax^2= bx+c, where a,b and c are real numbers and a is not zero?

If 30 lb of rice and 30 lb of potatoes cost ? $27.60? , and 20 lb of rice and 12 lb of potatoes cost ? $15.04? , how much will 10 lb of rice and 50 lb of potatoes? cost?