## Posts tagged ‘Dunkin Donuts’

### Money-Saving Fermi Questions

I was pissed when my cousin wouldn’t give me two $5 bills for a $10 bill.

“Sorry, can’t,” he replied simply.

When asked why the hell not — I knew he had two $5 bills, because he had gotten one from the gas station attendant earlier, and the waitress just brought him another — he explained that all $5 bills are put into savings.

“When I receive a $5 bill, I don’t spend it. It stays in my wallet till I get home, and then it goes right into the piggy bank,” he said. “Every couple months, I take those bills to the bank. It’s an easy way to build up my savings account.”

“So, what, you save like $50 a year this way?”

“It’s a helluva lot more than you’d think,” he replied.

As stupid as this sounds, now **everyone** in my family is doing it. It is a low-impact way to build up your savings account. And it leads to a great Fermi question:

- If all of your $5 bills go into savings, how much will you save in a year?

And for my sons, who don’t often pay for things with bills large enough to require $5 in change, we have the following:

- If all of your nickels go into savings, how much will you save in a year?

**Fermi questions** are questions that require quantitative estimates to arrive at an answer. It often requires making assumptions, because exact data is unavailable. Here are a few others:

- What percent of people who have ever lived are currently alive?
- How many hot dogs are sold at Yankee Stadium during a baseball season?
- How long would it take a snail to travel from Miami to Los Angeles?
- What is the weight of a million dollars? (Assume 1,000,000 one-dollar bills.)

My favorite Fermi question is based on a Dunkin Donuts radio advertisement, in which they boasted:

We reject more than one million pounds of coffee beans a year.

Which has to make you wonder:

- How picky are they, really?

### Math Jokes for National Doughnut Day

Today is National Doughnut Day, and if you need your fix, *Time* reports that free doughnuts are available from Dunkin’ Donuts, Krispy Kreme, Tastykake or Winn Dixie.

At MJ4MF, we can’t let this day pass without telling the obvious joke…

A topologist is a mathematician who can’t tell a coffee cup from a doughnut.

And the modification…

How many topologists does it take to change a light bulb?

Just one. But what’ll you do with the doughnut?

To help you celebrate, here’s a doughnut-related math problem.

Several years ago, Dunkin’ Donuts ran a commercial bragging about how picky they were. The commercial stated:

We reject more than one million pounds of coffee beans a year.

Sure sounds impressive, doesn’t it? But how picky are they, really? Do a back-of-the-envelope estimate, and I think you’ll realize that they’re not all that picky after all.

### Was Darrell Huff at the State of the Union Address?

Perhaps my all-time favorite joke:

How many school administrators does it take to change a light bulb?

Cha-a-a-a-a-a-a-a-ange?

Or, if you prefer:

How many school administrators does it take to change a light bulb?

What was wrong with the old light bulb?

These jokes seem particularly relevant after listening to last night’s State of the Union address. Here’s why.

President Obama made a bold statement about his plans for the future of education. “Over the next ten years, with so many Baby Boomers retiring from our classrooms, we want to prepare 100,000 new teachers in the fields of science, technology, engineering and math.”

Oh, please. I’m a Steel Town Democrat and generally an Obama supporter, but this is another instance of using a big number to sound impressive. Bill Clinton employed a similar tactic in his 1998 State of the Union address, when he announced funding for the training of 100,000 additional teachers to help reduce class size. Truth is, adding 100,000 teachers to the current pool of 3,000,000 teachers would only reduce class size by about 3% — which translates to 1 pupil fewer in a 25‑student classroom.

The problem is, 100,000 just isn’t enough. In 2007, Barbara Pytel claimed that hundreds of thousands will leave the teaching profession in the next few years as the baby boomer generation enters retirement. Her prediction for math and science was particularly dire. “It is estimated that the US will have a shortage of 280,000 math and science teachers by 2015” (*Baby Boomer Teachers Retiring: Study Predicts Major Problem by 2015*).

So what good will only 100,000 new teachers do? That’ll still leave a shortfall of 180,000.

In March 2009, Richard Ingersoll and David Perda of the University of Pennsylvania calculated that colleges and universities actually produce **150% more** math and science teachers than schools require to replace those who are retiring. That’s right. Annually, the number of new teachers is **2.5 times** the number that leave due to retirement.

The problem isn’t the number of new teachers or the number who retire. It’s the number of teachers who leave the profession for a better job. Statistics vary wildly, but some estimates say that 1/3 of new teachers leave the profession within 3 years, and up to 1/2 leave within 5 years.

Why do teachers leave? We all know the answers, and we have data to prove it. In the study by Ingersoll and Perda, they found that 59.9% of teachers said they leave the math classroom because of poor salary and benefits, and 67.5% said they leave because there was inadequate time to plan and prepare. Really? You mean teachers want time to do a good job, and they want to be adequately compensated for their efforts? Go figure.

Last night President Obama said, “In South Korea, teachers are known as ‘nation builders.’ Here in America, it’s time we treat the people who educate our children with the same kind of respect.” Yeah, no kidding. If you really believe that teachers deserve more respect, then please stop trying to deceive us with large numbers, Mr. President. Instead, how about some effort toward improving the salary and working conditions for our nation builders?

In his defense, I believe Obama is willing to take the steps necessary to resuscitate a broken system. Last night, I just kept wishing that he would have talked about his plans for reform that might actually fix the problem.

BONUS: Speaking of using large numbers to deceive, here’s a math problem for you. A radio commercial several years ago attempted to promote the selectivity of Dunkin Donuts. The commercial stated, “We reject more than 1,000,000 pounds of coffee beans a year.” Are they really that picky? Do a quick, back-of-the-envelope calculation to determine the percent that they reject. You can find information online about the number of Dunkin Donuts stores in the world, the amount of beans needed to make a cup of coffee, how many cups are sold, and so on. And even if you can’t, make some conservative estimates. You’ll still be surprised by the answer your calculation reveals.