When a relational expression is false, it has the value

What is the relationship between marginal external cost, marginal social cost, and marginal private cost? a. marginal social cost equals marginal private cost plus marginal external cost. b. marginal private cost plus marginal social cost equals marginal external cost. c. marginal social cost plus marginal external cost equals marginal private cost. d. marginal external cost equals marginal private cost minus marginal social cost. marginal external cost a. is expressed in dollars, so it is not an opportunity cost b. is an opportunity cost borne by someone other than the producer c. is equal to two times the marginal private cost d. is a convenient economics concept that is not real

Tom has brought $150,000 from his pension to a new job where his employer will match 401(k) contributions dollar for dollar. each year he contributes $3,000. after seven years, how much money would tom have in his 401(k)?

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?