Answer:
Mark's individual consumer surplus is $10.
Step-by-step explanation:
Mark and Rasheed are at the bookstore buying new calculators for the semester.
Mark is willing to pay $75 and Rasheed is willing to pay $100 for a graphing calculator.
The price for a calculator at the bookstore is $65.
The consumer surplus is the difference between the maximum price that a consumer is willing to pay and the price he actually has to pay.
Mark's individual consumer surplus
= Price mark was willing to pay - Price he actually has to pay
= $75 - $65
= $10