May someone help me with this please? Inverse equations

Beth makes batches of bluberry muffins and banna muffins. each batchis 6 muffins. she makes 2.5 batches of bluberry muffins. how many batches of bananna muffins should beth make if she wants to have a total of 60 muffins?

How do you use the elimination method for this question? explain, because i really want to understand!

Which of these tools or constructions is used to inscribe a hexagon inside a circle?