Leena spent $100 per month on pens (X) and CDs (Y) at the Enron company store. Pens cost $2, and CDs cost $5. In July 2015, Leena purchased 15 pens and 14 CDs. Her utilometer readings at the end of the month showed that the marginal utility of the last pen was 10 utils and the marginal utility of the last CD was 25 utils.
a. Write the equation for Leena’s pen/CD budget constraint.
b. True or False: Leena was at the tangency point between her budget constraint and an indifference curve.
c. Explain your previous answer (in several sentences and/or equations)