USPuzzle Contest: 5 – Bad Math Puzzles
I’ve fallen behind on puzzle posts, so look for another post near the end of this week.
This set of three puzzles revolves around bad mathematics. Each puzzle is worth 1 point if answered correctly.
1. The Conqueror Worm: A small worm is at the bottom of a 30-inch pit, and is trying to escape. Each hour, the worm crawls up 3 inches, then slides back down 2 inches. How long will it take the worm to reach the top of the pit?
2. The Truant Student: A student was called to the office to discuss his poor attendance. “But I don’t have time for school,” he said. “Here, I’ll prove it to you. I need 8 hours of sleep, which amounts to about 122 days a year. Weekends off – Saturday and Sunday – are a must, and that’s 104 days a year. Summer vacation is about 60 days. If I spend about an hour on each meal – you wouldn’t begrudge me meals, would you Mr. Principal? – that’s 3 hours a day or 45 days a year. And I need at least 2 hours of exercise and relaxation time each day to stay physically and mentally fit, which is another 30 days.
“Now add that all up: 122 + 104 + 60 + 45 +30 = 361. Out of a normal 365-day year, that only leaves 4 days to be spent at school, which I think you’ll find lines up perfectly with my attendance record so far.”
Obviously, this kid is full of it, but can you explain why?
3. The Confused Travelers: Three travelers stop for the night at an inn. The cost for a room is 30 silver, which they split evenly so that each of them pays 10 silver. Some hours later, the innkeep finds that the room should have been 25 silver, and he has overcharged the travelers. Being an honest fellow, he sends his boy to the travelers with 5 silver. To make the division easy, they each take 1 silver and send the boy on his way with the remaining 2 silver as a tip. Then the travelers say to themselves, puzzled: “We each paid 10 silver and got each got 1 back, so it’s as if we each paid 9 silver. Now 3 of us times 9 coins is 27, plus the 2 we sent of with the boy comes to 29. It seems as if 1 of the 30 silver we paid to start has disappeared.” Where did the missing silver go?
Answers go, as always, to usp.blogmatters@gmail.com Happy puzzling.
