Chapter 2, Problem 19CTQ

Suppose Alphonso’s town raises the price of bus tickets from $\$0.\text{5}0$ to $\$\text{1}$ and file price of burgers rises from $\$\text{2}$ to $\$\text{4}$.

Why is file opportunity cost of bus tickets unchanged? Suppose Alphonsn’s weekly spending money increases from $\$\text{1}0$ to $\$\text{2}0$.

How is his budget constraint affected from all three changes? Explain.