#122 Article of faith
Dithering Dan has just received his monthly copy of Doubtful Daze magazine. Unsure which article to read first, he turns to a random page and counts a certain number of pages forwards, increasing the page number. He then counts half of his previous page count back, then half the previous count forwards, and finally half the last count back. The page number he finishes on turns out to be four times the one he started at. There are fewer than 50 pages in the magazine and the pages are numbered consecutively starting at page 1.
What page number does he finish on?
Answer next week
#121 Creative addition
Solution
The classic 鈥淎ha!鈥� solution is to turn the 9 upside down to make 6, so both columns add to 21.
But you can also place the 1 card on top of the 5 card, so the 5 is hidden and both columns add to 20. Or turn the 5 card upside down to reveal its blank side and place it on the 2 to hide both numbers (columns add to 19).
Or you can put the 3 top right of the 2 to make it 23 (= 8), so the columns are both 24. Or what if you pour paint over all but 1, 2, 3 and then move 3 to the other column? Fair or meh? You decide.
Quick quiz #110
1 What was the purpose of a sphygmograph?
2 How many comets were discovered by self-taught astronomer Jean-Louis Pons?
3 Who created the first effective vaccine against epidemic typhus?
4 What is the sieve of Eratosthenes an efficient means of finding?
5 What is the name of the ring of bone found in the eyes of many vertebrate species?
Answers
1 It was used to measure blood pressure in the 19th century
2 37. Pons discovered more comets with the eye than any other person in history
3 Rudolf Weigl
4 Prime numbers
5 The sclerotic ring