#63 What day?
鈥淚t鈥檚 Monday today, isn鈥檛 it?鈥� pondered Angie.
鈥淚 seem to remember yesterday was Tuesday,鈥� said Beatrice. 鈥淚 believe we鈥檙e as far from Sunday as we are from Wednesday,鈥� said Carol.
鈥淲hen the day after tomorrow becomes 鈥榶esterday鈥�, 鈥榯omorrow鈥� will be Tuesday,鈥� interjected Dorothy, cryptically.
鈥淚t鈥檚 not the weekend,鈥� said Ethel.
Clearly there was some disagreement 鈥� and if I told you how many of them had got it right, then you would be able to work out what day it is today. However, I鈥檝e decided to keep it a secret. So who was right, and what day is it?
Answer next week
#62 Burger run
Solution
Yolanda鈥檚 estimate is closest 鈥� there are 23 shortest routes from A to B that pass through exactly one Big Burger. One way to solve this kind of puzzle is to systematically work from A and keep track of how many ways there are of reaching each point. With this problem, you should keep a separate count of how many ways there are of reaching each point after (a) zero or (b) one Big Burger visit. For line segments that contain a Big Burger, (b) becomes equal to (a), then (a) becomes equal to 0, with the 鈥渙ld鈥� value for (b) effectively discarded.
Quick quiz #55
1 Which predator, renowned as the fastest in the animal kingdom, bears the name Hayabusa in Japanese?
2 The name also lends itself to the fastest production example of what type of vehicle, one that could reach a similar top speed?
3 There is a third Hayabusa, one that outpaced both of them. It arrived back from 25143 Itokawa on 13 June 2010 bearing what?
4 Istiompax indica holds the animal speed record in the sea; what is the common English name of this prized game fish?
5 The fastest human-made object reached a speed of nearly 350,000 kilometres per hour in 2018. What is it and what was it doing?
Answers on page 54
Quick quiz #55
1 The peregrine falcon, Falco peregrinus. Its swooping dives reach over 300 km/h
2 A motorcycle made by the Japanese firm Suzuki since 1999
3 An asteroid sample. The Japan Aerospace Exploration Agency probe was the first mission to land on one and take off again successfully
4 Black marlin. It has been recorded reeling out a fishing line at over 120 km/h
5 NASA鈥檚 Parker Solar Probe; it was making a close pass around the sun
Answers