7. (Appendix 4.A) Consumers typically pay a higher real interest rate to borrow than they receive when they lend (by making bank deposits, for example). Draw a consumer's budget line under the assumption that the real interest rate earned on funds lent, rz, is lower than the real interest rate paid to borrow, rb. Show how the budget line is affected by an increase in rb, an increase in rb, or an increase in the consumer's initial wealth. Show that changes in rz and rb may leave current and future consumption unchanged. (Hint: Draw the consumer's indifference curves so that the consumer initially chooses the no-borrowing, no-lending point.)