Based on intermediate microeconomics. Preferences, indifference curves and budget constraint.

Leo consumes only apples and bananas. He prefers more apples to fewer, but he gets tired of bananas. If he consumes fewer than 24 bananas per week, he thinks that 1 banana is a perfect substitute for 1 apple. But you would have to pay him 1 apple for each banana beyond 24 that he consumes. The indifference curve that passes through the consumption bundle with 31 apples and 36 bananas also passes through the bundle with A apples and 18 bananas, where A equals