Ask the Fool: What’s a “pure play” company? – M.J., Tucson, Ariz.

A: Unlike conglomerates, a pure play is a company that focuses on a single business. When investors are drawn to a particular industry, they might look for a company that’s a pure play, so their invested dollars won’t be spread out over other, less desirable businesses.

If your research suggests that the light bulb industry is one of the most attractive and profitable ones around, you might invest in General Electric, which makes everything from light bulbs to airplane engines. Or you might try to find a pure-play light bulb company.

The hypothetical Bright Idea Light Bulb Co. (ticker: UREKA) might fit the bill. Funds in UREKA would be focused solely on light bulbs, while GE also makes everything from security systems to aircraft engines, with each operation having varying profitability characteristics.

Coca-Cola is a beverage pure play, unlike PepsiCo, which has a giant snack operation in Frito-Lay. Barnes & Noble is a bookselling pure play, while Amazon.com sells books and much more.

Ask the Fool: Where can I go to figure out how much inflation has occurred within a certain time span? – B.C., Midland, Mich.

A: Click over to the Web site of the Department of Labor’s Bureau of Labor Statistics and you’ll find a handy inflation calculator: data.bls.gov/cgi-bin/cpi calc.pl. If you want to know how much buying power $100 in 1970 would have today, just ask. The answer: $564. (Another good calculator: www.westegg.com/ inflation.) To learn the average inflation rate over a period, visit www.measuringworth.com/growth and select “Consumer Price Index.” (From 1977 to 2007, it was 4.2 percent.)

My dumbest investment: My dumbest investment was in Intel stock. I bought 100 shares in 1995 at what was then $62 per share. They advanced to $78. Then my broker advised me to enter a “stop-loss” order to protect my profits. Duh … sounded like a good idea. Sure would hate to lose those profits. So we placed an order to sell if the shares fell to $74. Of course, they did, and my shares were sold.

A few years later, they were at $165!

Thump! That’s the sound of me kicking myself. – Matt Sigman, Santa Clarita, Calif.

The Fool responds: Your purchase price, adjusted for splits, would be around $7.30 per share, and Intel was recently trading around $14.20, which would have doubled your money in 13 years. That’s an annualized growth rate of about 5 percent. You’d have increased your investment 10-fold, though, if you’d sold in 2000, before the bubble burst.

We’re wary of stop-loss orders. Yes, one can protect your profits, but it can also kick you out of something that will rise to great heights later, just because it temporarily dips. Proceed with caution.

Foolish trivia: You might not know my name, but I’m a multinational holding company with subsidiaries making high-performance coatings, sealants and specialty chemicals, primarily for maintenance and improvement.

I rake in more than $3 billion yearly. I’ve posted 60 consecutive years of record results, issued 11 stock splits since 1975, and completed more than 100 acquisitions in the last 40 years. I’ve also upped my annual cash dividend for 34 years in a row.

My brand names include Zinsser, Rust-Oleum, DAP, DIF, Bondex, Plastic Wood, Varathane, Testors, Day-Glo, Dryvit, Carboline, Euco, Fibergrate and Stonhard, among others. Who am I?

Answer to last week’s trivia: I’m a top global brand, having begun with a handful of beans in Seattle’s Pike Place Market in 1971. In 1991 I became the first privately owned U.S. company to let part-time workers participate in a stock option program. I went public in 1992.

You’ll find my more than 10,000 retail locations in China, Kuwait, Indonesia, Switzerland, Peru and elsewhere.

I offer more than 30 blends of coffee, along with teas, other beverages, foodstuffs, music and more. Customers have loaded more than $2.5 billion onto my cards. I was a first-mate pursuer of Moby Dick.

Who am I? Answer: Starbucks.

The Motley Fool Take: Credit card runner-up MasterCard (NYSE: MA) reported better-than-expected third-quarter earnings recently – impressive for a financial company these days. Revenue was up 24 percent over the year-ago quarter, and net income rose 7 percent.

Shares have been lopped in half over the past six months, amid fears of recession. But MasterCard is still growing at a pretty healthy clip: Purchase volume increased 13 percent to nearly half a trillion dollars, while total transactions grew 13 percent, to 5.4 billion.

As has been the case for a while, global growth led the way, with 25 percent purchase volume growth in the Asia/Pacific region, 25 percent growth in South Asia/Middle East/Africa, and 19 percent growth in Latin America. Few complaints there.

U.S. purchase volume grew at a much more modest 7 percent, by far the slowest-growing segment.

Shares have recently been cheap enough, in the $160 range, to justify buying, but the near-term future is bound to be anything but easy. A prolonged global recession could keep consumers suppressed and spending less.

If you have the guts to dip your toes in, you’d be well-advised to check your lofty expectations at the door, have a long-term time horizon, and be prepared for an all-out fallout of the global consumer market over the next year or two.

The Motley Fool is written by Tom and David Gardner for Universal Press Syndicate. The Motley Fool tells the truth about investing. Reach the Gardners at fool@fool.com, or by regular mail to Motley Fool, PO Box 19529, Alexandria, VA 22320-0529.