Help with these 2 please

Graph red beads cost $1 an ounce and gold beads cost $3 an ounce. juanita wants to purchase a 12-ounce mixture of red and gold beads that she can sell for $2 an ounce. the solution of the system shows the number of beads needed for juanita to break even. x + y = 12, x + 3y = 24 how many ounces of red beads will juanita buy to break even? how many ounces of gold beads will she buy?

Afamily went out to dinner and their bill was $113.if they want to leave a 19% tip, how much should they leave.

What is the gcf of 20c^3-5c^4+30c^6