5. LO 2, 5 A consumer receives income y in the cur- rent period, income y' in the future period, and pays taxes of t and t' in the current and future DIXON TICON periods, respectively. The consumer can borrow and lend at the real interest rate r. This consumer faces a constraint on how much he or she can bor- row, much like the credit limit typically placed on a credit card account. That is, the consumer can- not borrow more than x, where x