FIGURE 3 CHANGES IN INCOME ON A BUDGET LINE
Budget line a shows the consumption choices available with a budget of $50 and prices of pizza and wall climbing at $10 and $20, respectively. When the budget increases to $100, the budget line shifts parallel outward to budget line b, doubling the quantities that can be purchased. When the budget falls to $20, the budget line shifts inward to budget line c, reducing the amounts that can be purchased.