Which of the following is the kind of decision that can be made at the margin?
a. whether or not to add an extra room to a home.
b. whether or not to hire new workers.
c. whether or not to go on a vacation.
d. whether to have a dog or a cat as a pet.?

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.