Suppose that during a recent 35-year ?period, there were sixvolcanic eruptions sufficiently powerful to reduce the amount of power generated by solar panels by at least 25 for a period of a year. Call these? "Class D25 volcanoes. Suppose that the return on investment from installing solar panels is often calculated over a 20 year period. What is the probability? that, during a 20?-year ?period, there will be two or more? "Class D25" volcanic? eruptions?