6. (Appendix 4.A) Draw a budget line and indifference curves for a consumer who initially is a borrower. Be sure to indicate the no-borrowing, no-lending point and the optimal consumption point. Then show the effect on the budget line and the consumer's optimal consumption of an increase in the real interest rate. Using an intermediate budget line, show the income effect and the substitution effect. Do they work in the same direction or in opposite directions? Explain your answer.