Summer is just about over, but we expect most Motley Fool Answers listeners didn't "sell in May and go away" -- you've been keeping up with matters of finance and investing all along...right?

However, if you happened to take a break from thinking about your money during beach season, you might have missed a few of Alison Southwick and Robert Brokamp's monthly mailbag shows. In which case, you wouldn't have noticed that Ross Anderson -- certified financial planner from Motley Fool Wealth Management, a sister company of The Motley Fool, and a regular on the mailbag podcasts this spring -- took a break from his guest hosting duties as well, so that other Fools could get their time in the sun. Now, he's back to help the podcasting duo address another batch of listener queries.

In this segment, they tackle a complex set of questions around rental income, self employment, a raft of tax-advantaged retirement account options, and one couple's best choices for reducing what they'll owe to Uncle Sam.

A full transcript follows the video.

This video was recorded on Aug. 28, 2018.

Alison Southwick: Our next question comes to us from Cary. "My husband and I are in our early forties and have three rental properties that earn us $55,000 as reported on Form 1099. I would prefer to not have this income included as taxable income. I heard about freelancers setting up a solo 401(k) where you can contribute 100% of your income up to $18,500, but I'm not sure if we would be considered self-employed. Can you contribute to an employer 401(k) and solo 401(k) in the same year? Also, is there such a thing as a solo Roth 401(k)? We have a Roth 401(k) through an employer but had to stop contributing due to income restrictions."

Ross Anderson: There is a lot to unpack in that question for Cary and a couple of things I just want to make sure we straighten out.

First of all, when you're looking at a Roth IRA, Roth IRAs have an income cap to them where if you're making too much money, they stop allowing you to contribute to them. Roth 401(k)s actually don't suffer from that same thing, so if you have a Roth 401(k) option available to you, you are always able to defer up to the $18,500 that you can into a traditional 401(k) into a Roth 401(k) as long as you've got that option, or the catch-up if you're beyond age 50. That's the first thing. I want to make sure Cary knows that she could still do the Roth 401(k) if she thinks that that's a good option.

However, if she wants to set up a solo(k), or an individual 401(k), or any of the monikers that they go by, they can set that up also as a Roth. You could have a Roth solo(k) if you wanted to. The amount of money that you can contribute to it, though, doesn't necessarily change. You're able to defer $18,500 of your income per year regardless of how many plans that you have.

Now where this gets a little bit complicated is that you could do, as the employer, a profit share. She could do a profit-sharing plan and contribute a percentage of the business earnings. You could also do that in a SEP-IRA, for example. That may be easier and cheaper to set up and administer. The SEP is going to be pre-tax money. You can't do a Roth SEP-IRA.

And now that I've got everybody totally confused, the goal was to do some Roth money and some pre-tax money to defer the income. Cary mentions that she's not wanting to pay the taxes on that rental income, so she maybe consider doing a SEP-IRA for the rental properties as a self-employed person. Easy to administer. Low cost. And going back to the Roth 401(k) through the employer and getting both of those options at the same time.

Robert Brokamp: And she said she'd prefer not to have this income included as taxable income. If she's going to put it into some sort of retirement account, it has to be a traditional because if you put it in a Roth, it is taxable in the year you receive it. The benefit is that the money comes out tax-free as long as you follow the rules.

Anderson: Exactly. Now, the thing on the pre-tax anything is that you're not going to avoid these taxes forever. It feels good to eliminate them now, and the standard thinking is that if you're going to be in retirement when you're taking the money out, you're in a lower tax bracket. That's not always true, so I'm not always a proponent of put everything in pre-tax that you can to get the lowest tax bill this year, but if that's what they're trying to do, a SEP or a traditional will really give you that flexibility.

Brokamp: And I would finally say, Cary, if you have someone who does your taxes who's a CPA, you might want to talk to her or him about that because she can talk through the differences between the SEP and the solo 401(k) and any other options you have.

Anderson: Without a doubt. Before making any of those decisions, a tax professional is recommended.

Ross Anderson is an employee of Motley Fool Wealth Management, a separate, sister company of The Motley Fool, LLC. The information provided is intended to be educational only, and should not be construed as individualized advice. For individualized advice, please consult a financial professional. The Motley Fool has a disclosure policy.