National defense is a classic example of a public good because a. everyone agrees that some level of national defense is important, but only the government knows the optimal amount. b. there is no market for private security services. c. it is difficult to exclude people from receiving the benefits from national defense once it is provided. d. there are no private firms willing to supply defense goods such as tanks and weapons.

Quick calculate the roi dollar amount and percentage for these example investments. a. you invest $50 in a government bond that says you can redeem it a year later for $55. use the instructions in lesson 3 to calculate the roi dollar amount and percentage. (3.0 points) tip: subtract the initial investment from the total return to get the roi dollar amount. then divide the roi dollar amount by the initial investment, and multiply that number by 100 to get the percentage. b. you invest $200 in stocks and sell them one year later for $230. use the instructions in lesson 3 to calculate the roi dollar amount and percentage. (3.0 points) tip: subtract the initial investment from the total return to get the roi dollar amount. then divide the roi dollar amount by the initial investment, and multiply that number by 100 to get the percentage.