Earlier today I set you the following riddles:
1. A retired professional wrestler boards a crowded train in Chicago when a young man stands up to offer his seat. The wrestler is not injured and is only 36 years old. All week, riders on the train offer to give up their seat so that the famous wrestler can sit down instead. Why do people keep offering their seat to this muscular former athlete?
2. Penelope works at the Clocktower Lodge at the top of a mountain ski resort. Early one morning, she arrives at the lodge to discover that someone forgot to wind the clock, and it has stopped running. The eponymous clocktower is the only way to tell time on the top of the mountain and no one else is due to arrive at the lodge for several hours. So, Penelope hops on the chairlift, rides down to the bottom of the mountain, notes the correct time and then rides the chairlift back up to the lodge. If Penelope has no way of telling time while traveling up and down the mountain, how can she be sure to set the clock correctly upon returning to the lodge?
3. One day, Harold cleans out a large glass pickle jar, places it on his desk and drops in a few coins. He decides that each day, he will dump his loose change into the jar and that once the jar is full, he will treat himself to a fancy steak dinner. Three months later, a blind man named Richard visits Harold’s office for the first time. Harold tells Richard about the coin jar he keeps on his desk. The blind man carefully picks up the jar, shakes it once and names the exact amount of change in the jar. “Incredible!” exclaims Harold. He shakes the blind man’s hand and invites him to join him for a steak dinner once the jar is completely full of coins. About how long will it be until then?
Solutions
1. The wrestler is a woman and pregnant.
2. Penelope winds up the clock and it starts working. When she hops on the chairlift she takes a note of the time on the clock. She travels down the chairlift, gets the correct time, and returns immediately on the chairlift to the lodge. She notes the new time on the wind-up clock. Since the time down the chairlift is the same as the time up, she divides this length time by two, giving an amount that she adds to the time from the bottom of the mountain to give the correct time at the top.
This puzzle relies on the solver presupposing that the clock is broken, which it isn’t. It is a wind up clock that has not been wound up.
3. Three months. The only way the blind man can tell the exact amount of the change is if the jar is empty. Which means that Harold has just had his steak dinner and emptied the jar. So it took about three months to fill the jar with coins.
Thanks again to Adam Rubin from Art of Play for today’s puzzles.
My latest book Visions of Numberland: A Colouring Journey Through the Mysteries of Maths, co-written with the mathematical artist Edmund Harriss, is out this week. It contains a gallery of images from maths, with explanations, to colour in or just contemplate in black and white.
I set a puzzle here every two weeks on a Monday. Send me your email if you want me to alert you each time I post a new one.
I’m always on the look-out for great puzzles. If you would like to suggest one, email me.
