Q. Can you explain this tax situation? We are in the 15 percent tax bracket. Our taxable income is less than $73,800, filing a joint return for the 2014 tax year. ? But we take Required Minimum Distributions from our IRAs because we are both over 70-1/2 years old. ?

If we take another $100 distribution from an IRA, line 15b on our 1040 goes up by $100. Then the Social Security worksheet line 11 increases by $100 (Note: our line 7 is more than $44,000) and Social Security worksheet line 15 increases by $85 (also lines 16 and 18).

Then our form 1040 taxable income, line 43, goes up by $185?and our tax bill goes up about $30. So I’m now taxed 30 percent on the $100 of additional income.

Is this correct? What is wrong with this? —J.C., by email?
? ?
A. It’s correct. Your actual tax will be about $185 times your 15 percent tax bracket. This means you will pay $27.75 in additional income taxes for your additional IRA withdrawal of $100. So what economists call your marginal tax rate— the rate you pay on a dollar of additional income—is 27.75 percent, not 30 percent.

But you know, and I know, that the difference is quibbling. The real issue is what you’ve just been hit in the face with— you are paying a lot more in income taxes as a retiree than you expected to pay. For many the added tax of Social Security benefits literally means a doubling of their income tax bill.

Equally important, the burden of that tax falls entirely on the money you have saved in your qualified retirement plans. In effect, you are paying a penalty for being a saver when our friends in Congress, regardless of party, continue to talk about the need to encourage people to save more.

There have been efforts to repeal the tax. So far, they have gone nowhere. And don’t expect any help from the AARP. At the end of January, however, the President of the Association of Mature American Citizens again continued to support of the Senior Citizens Tax Elimination Act (HR 589). The AMAC is a conservative counterpart to the AARP. You can learn more about the bill on the AMAC website, www.amac.us.

Will AMAC make progress eliminating the tax? Sorry, the bill doesn’t have nearly enough sponsors. According to the website govtrack.us, which tracks legislation, the bill has only a one percent chance of getting past committee and a zero percent chance of being enacted.

My suggestion? If you are a retired middle-income taxpayer, calculate the federal income tax you have to pay. Then calculate the tax you would pay if Social Security benefits were not taxed. Figure out the difference. Then tell your Congressman about it and that you want the tax repealed.

If H. & R. Block does your taxes, as it does for millions of people each year, tell them that doing the calculation is part their advertising promise to help “get your billions back.”

And, yes, we are talking billions. According to estimates by the Social Security Trustees, the taxation of benefits will bring in $33 billion this year.

Q. I have a 25-year-old daughter who probably should start diversifying her assets. She earns $42,000 annually and has $68,000 saved between savings and checking. Her employer matches a 5 percent contribution to an IRA of moderate risk.

She currently rents and has no dependents, but that will likely change in the future. How would you suggest she begin investing her money, and how much should be held in reserve for illness, a home purchase, etc.? —C. D., by email

A. Sounds like your daughter is a super-saver. As a young worker, she is probably quite mobile. So she can be secure with a reserve of six months of her current spending. That’s maybe $15,000, if she saves as much as she appears to save. The remainder of her $68,000 stash—$53,000— should be invested longer term.

It could be entirely in a broad stock market fund, such as one of the total market exchange traded funds. Or, if she is cautious or worried about job stability, it could be in my 50/50 Couch Potato portfolio— half domestic stocks, half U.S. Treasury inflation protected bonds. The more cautious approach could also double as her home purchase fund since the bond portion could be sold at any time to provide the down payment.