If you understand please help

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?

Afair survey question is one that does not encourage biased responses. which survey question is fair? a.) do you agree that only unethical people take credit for other people’s work? b.) have you ever taken credit for somebody else’s work? c.) have you ever engaged in unethical behavior, such as taking credit for somebody else’s work? d.) don’t you think it is unethical to take credit for somebody else’s work?

How can you check that you have correctly converted frequencies to relative frequencies?