问题如下：
Lorraine Newman is evaluating whether to save for retirement using a TDA or a taxexempt account. The TDA permits tax-deductible contributions but withdrawals will be taxed at 30 percent. The tax-exempt account permits tax-free accumulation and withdrawals but contributions are taxable at a 40 percent tax rate. Assuming contribution limits do not affect Newman’s choice of accounts, which account should she choose?
选项：
A. TDA.
B. Tax-exempt.
C. The choices are the same.
解释：
A is correct.
The future accumulation of the TDA is (1 + r)n(1 − 0.30), whereas the future accumulation of the tax-exempt account is (1 + r)n(1−0.40). Therefore, the TDA will accumulate more wealth.
如果从早交税不如晚交税的角度看，是不是即使税率一样也应该选TDA？
