Durability.

A firm rents light bulbs to consumers. The firm covers the cost of the light bulb and replacing it every time it burns out. The interest rate is 13%. The cost of producing a light bulb is Squareroot N where N is the number of years the light bulb lasts. In the following cases, what is the firm's present value cost of providing a lightbulb to a consumer and replacing it every time it burns out forever? (a)Using light bulbs that last 1 year _____ (b)Using light bulbs that last 2 years _____ (c)Using light bulbs that last 10 years _____