A water filter seller can manufacture a water filter that lasts exactly two years at a cost of $0.90 per filter. The seller can also manufacture a water filter that lasts exactly one year at a cost of $0.40 per water filter. A one-year water filter can be sold for $4. If the interest rate is 5%, what is the price of a two-year water filter?

Based on the information from the previous question, what is the present value of the firm's profit from selling two consecutive one-year water filters?

Based on the information from the previous two questions, what is the present value of the firm's profit from selling one two-year water filter?