How much time does speeding save?
Bob has a simple commute: he drives 60 miles, traffic-free, on a highway. Normally Bob drives with the flow of traffic at 70 miles per hour. One day he is anxious and instead speeds at 80 mph. How much time does he save? How much time would he save at 90 mph?

Is a calorie burned the same as a calorie eaten?
Suppose you are on a strict diet of eating 1700 calories per day. One day you relax and have a can of Coke, adding an extra 140 calories to your intake. A few hours later you feel guilty and hop on the treadmill. You run until the calories burned reads 140 calories. Will ...

A fun chess puzzle
Chess isn't something I normally write about, but this puzzle was too interesting to pass up. Why? This puzzle stumped some very smart people, including Ken Thompson (one of the people behind Unix and C), and even world class chess players like Garry Kasparov, Anatoly Karpov, and Mikhail Botvinnik, according to an ...

Warren Buffett’s other political proposal
Warren Buffett has recently been making headlines with the controversial "Buffett Rule" calling for a tax raise on millionaires. But this isn't the first time Buffett has said something interesting politically. Now is a good time to recount an amusing proposal he made in an op-ed in 2000 about political campaign finance ...

Monday puzzle: a really tough interview question
Many of my Monday puzzles have been technical interview brain teasers. Sebastian emails me an interview question that is a really difficult math problem. Hi Presh, This is a question I once got asked in an internship interview. The interviewer told me it was a hard problem, that would take at least 20 ...

If a friend is wasting money, should you speak up or keep it to yourself?
via images_of_money I sometimes cringe when I hear how some people throw away their hard-earned money. A few stories that come to mind are: --Someone in credit card debt got a $100 tuition overpayment refund. He chose to use the money to buy a video game rather than pay off debt --A friend ...

Which has better rewards: BankAmericard vs Amex Blue Preferred rewards card?
This is an interesting question that could be asked in a consumer ed class. Suppose Alice is shopping for a cash-back rewards credit card. She is considering between the BankAmericard and the American Express Blue Preferred credit cards. Here are the details of those cards, at the time of this writing. SUMMARY OF REWARDS Category BankAmericard Amex ...

No, retiring early won’t kill you: understanding studies of retirement and longevity
I understand that retiring is never an easy decision. People wonder about how they will spend their time, and whether they will be happy outside of a job. I get that. But what I don't like is the unusual fear-mongering about change. Reputable magazines publish some things that scare people into ...

When game theory backfires: a case study of Robert Campeau’s takeover bid
In 1988, Canadian financier Robert Campeau was attempting a takeover of Federated, a retail congomerate that owned Bloomingdales. The negotiations were quite interesting, and in 1990 Fortune magazine went so far as to call it "The Biggest, Looniest Deal Ever." One of the notable strategic elements was a "two-tiered offer" that Campeau ...

Monday puzzle: elevator buttons malfunctioning (spoilers)
An elevator in my office building of 65 floors is malfunctioning. Whenever someone wants to go up, the elevator moves up by 8 floors if it can. If the elevator cannot move up by 8 floors, it stays in the same spot (if you are on floor 63 and press up, ...

A trick to getting more booze in bars
image by Kyle May This tip comes just in time for the weekend. I read about the trick on Bundle, a great personal finance site. This article points out how you can possibly get more alcoholic drinks in bars, if you say the right words. Here are the details:

Puzzle: how would you divide the land equally? (spoilers)
While I normally post math puzzles on Monday, I found another interesting puzzle so there is a bonus problem this week. Here is the problem. A father dies and wants to divide his land evenly amongst four sons. The plot of land has the following unusual shape: How can you divide the land ...

A fair division storytale
While I was browsing random videos on Youtube, I came across an amusing story about fair division told by some Indian school children. The video is about five minutes long and I found it enjoyable. And if the accents are throwing you off, you can read my transcription of the video ...

Probability question: would you play this card game?
Today I want to share a fun card game that is a twist on drawing to the high card. The game is played with a deck of cards numbered 1 to 100, and its rules are as follows. First, you and I each draw one card from the deck and show them ...

Monday puzzle: measuring ball bearings
This is an easy puzzle I came across. You are given a container that holds 24 ounces of ball bearings. You have a balance but no weights for the scale. You want to measure exactly 9 ounces. How can you do it? Give it a try before reading the answer below. image by winnifredxoxo