Pls if anyone knows the answer that will be greatly appreciated :) question 1 btw

How do you solve a question like this?

Liz is shipping a package to her friend. the maximum weight of a medium flat-rate box is 20 pounds, including the box which weighs 6 ounces. write and solve an inequality to describe the possible weight ,w, of the contents that liz will ship to her friend if she must use a medium flat-rate box.

Asystem of equations has 1 solution. if 4x-y=5 is one of the equations , which could be the other equation ?