Enigmas & puzzles

February 20, 2005
Circumnavigationology

In the early hours of the morning, the next edition of News Interpretational was going to press. All was on track until the sports reporter announced: "I need help with this headline about the round-the-world yacht race between Elaine Mercator and Arthur McLellan. I can't work out if it should be ELAINE GETS THE GLORY or ARTHUR SNEAKS HOME BY A WHISKER."

"Tricky," said the obituary writer, who was the only other journalist around at that moment. "Did you look on the internet?"

"Of course, that's where I got the story from. But the report doesn't say who won. Both boats left Portsmouth at the same time, heading for Sydney, and whoever got back to Portsmouth first would win. Elaine's boat averaged 30 knots on the outward leg, but only 20 knots on the return leg because her keel fell off. Arthur's boat did a steady 24H knots on both legs."

"Isn't it obvious? Surely Elaine - "

"Ah, but she might have had to make a detour, losing ground. Or she might have stayed over longer in Sydney."

The obituary writer tilted the screen to see better. "Hmm… says here that each of them travelled exactly 18,000 nautical miles on each leg, and each stayed two days in Sydney to make repairs and take on provisions. So no detours or delays."

"Which means…"

"Elaine won, with a higher average speed of 25 knots."

The sports reporter started to type in the headline, then paused. "Are you sure?"

"Of course. Why?"

"We'll look pretty silly if it was Arthur."

Who won, Elaine or Arthur?



Scroll down for the answer


The answer

The obituary writer was wrong—Elaine's average speed was not 25 knots. She took 18,000 ÷ 30 = 600 hours to reach
Sydney and 18,000 ÷20 = 900 hours to return, a total of 1,500 hours (and an aggregate speed of 24 knots).
Each way, Arthur took 18,000 ÷ 24.5 = 734.7 hours, a total of 1,469.4 hours. So Arthur won.

The winner was Ian Constantinides of Bridgwater