1. Two investments earn an annual income of $575. One investment earns an annual simple interest rate of 8.5%, and the other earns an annual simple interest rate of 6.4%. The total amount invested is $8000. How much is invested in each account?

2. A plane flying with the jet stream flew from Los Angeles to Chicago, a distance of 3055 mi, in 5 h. Flying against the jet stream, the plane could fly only 2520 mi in the same amount of time. Find the rate of the plane in calm air and the rate of the wind?

3. A carpenter purchased 60 feet of redwood and 80 feet of pine for a total cost of $286. A second purchase, at the same price, included 100 feet of redwood and 60 feet of pine for a total cost of $396. Find the cost per foot of redwood and of pine.