Diana is a personal trainer whose client charles pays $80 per hour-long session. charles values this service at $100 per hour, while the opportunity cost of diana's time is $75 per hour. the government places a tax of $10 per hour on personal trainers. before the tax, what is the total surplus? a. $25 b. $20 c. $5 d. $0

Retirement investment advisors, inc., has just offered you an annual interest rate of 4.4 percent until you retire in 40 years. you believe that interest rates will increase over the next year and you would be offered 5 percent per year one year from today. if you plan to deposit $13,000 into the account either this year or next year, how much more will you have when you retire if you wait one year to make your deposit?