Please help with this

Hi, can anyone show me how to do this problem? 100 points for this. in advance

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?

Aband wants to create a cd of their last concert. to creat the cds, the cost will be $350 advertisement fee plus $3 per cd.write an inequality that represents how many cds they can buy with a maximum of $1225.solve the inequality