A new 2-lane road is needed in a part of town that is growing. At some point the road will need 4 lanes to handle the anticipated traffic. If the city's opti- mistic estimate of growth is used, the expansion will be needed in 3 years. For the most likely and pes- simistic estimates, the expansion will be needed in 6 and 10 years, respectively. The expansion will cost $4.9 million. Use an interest rate of 7%. (a) What is the PW for each scenario, and what is the range of values ? (6) Use Equation 10-1 to find the mean value of the expansion's PW