Given the sequence 7, 14, 28, 56, which expression shown would give the tenth term?

Someone me i need with this stuff

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?

Fred and gene are hang gliding. fred is 700 feet above the ground and descending at 15 ft/s. gene is decending as shown in the table. interpret the rates of change and initial values of the linear functions in terms of the situations they model. show all work. freds equation is f(x)=-15x+700. ( genes is the table attached)