would you please help me answer this question??? thanks

Question

mary wants to spend $70. at most for gifts but only has 60 cubic inches of space in her suitcase. rings cost $7 and take up 3 cubic inches of space and scarfs are $5 and take up 15 cubic inches. Write a system of four inequalities that model mary's
purchases. Let x = number of rings
and y = number of scarf.

I put:
equation 1: 3x(3 cubic inches)+15x(15 cubic inches) =< 60 cubic inches
equation 2: 7x + 5y =< $70

equation 3 ??

equation 4 ??