A replacement analysis is being done for a vacuum seal on a spacecraft. The current seal can be used for 10 more years, or a new one can be purchased and used instead. The new seal would cost $25,000, and there would be an annual $5,000 of maintenance cost. It is estimated the seal could be sold for $7,000 in 10 years.The current seal can be sold now for $9,000, or for $2,000 in 10 years. The required annual maintenance cost is $7,500.

Using 10 years for both alternatives, and 12% cost of capital, calculate the present worth of both the defender and the challenger, and determine whether the seal should be replaced.