Explain why the practice described in the following scenario is not sustainable. there has recently been high demand for wheat and wheat-based products in the united states. to cash in on this boom, a farmer devotes every field on his farm to growing wheat for four years in a row.

Anew 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 optimistic estimate of growth is used, the expansion will be needed in 4 years and has a probability of happening of 40%. for the most likely and pessimistic estimates, the expansion will be needed in 8 and 15 years respectively. the probability of the pessimistic estimate happening is 20%. the expansion will cost $ 4.2 million and the interest rate is 8%. what is the expected pw the expansion will cost?