#64 Ruritanian carpet
The newly built reception room at the Ruritanian embassy is circular. In the middle, there is a large circular pillar. All very stylish, but now it needs to be carpeted. Of course, the carpet will need to be doughnut shaped, with a hole in the middle where the pillar is. Fernando the carpet fitter needs to know the area he has to cover. This would be easy if he knew the radius or diameter of both circles, but nobody seems to know where the plans are, and when he tries to measure the diameter of the room, the pillar gets in the way. Fernando doesn鈥檛 like measuring around corners, so the only thing he can think to do is to measure across the room with the tape measure touching the pillar. That distance is 10 metres. How much carpet will he need?
Answer next week
#63 What day?
It is Friday, so Carol, Dorothy and Ethel are right. Carol and Dorothy think it is Friday, Angie thinks it is Monday, Beatrice thinks it is Wednesday and Ethel thinks it is any day but Saturday or Sunday. If I told you nobody is right, it could be Saturday or Sunday. If one person is right, it could be Tuesday or Thursday. If I say two people are right, it could be Monday or Wednesday. But if I say three people are right, it can only be one day: Friday.
Quick quiz #56
1 21:43 UTC on 20 June marks this year鈥檚 June solstice the point at which the northern and southern hemispheres are doing what, maximally?
2 What name is given to the plane in which Earth orbits around the sun, against which this is measured?
3 The name 鈥渟olstice鈥� refers to which apparent phenomenon that occurs at this time?
4 How many hours of daylight could you expect in the world鈥檚 most northerly national capital around the June solstice?
5 And how many in the world鈥檚 most southerly capital?
Answers on page 54
Quick quiz #56
1 Tilting towards (northern) or away (southern) from the sun; the longest and shortest days of the year respectively occur then
2 The ecliptic plane
3 The sun 鈥渟tanding still鈥� in the sky, reaching its highest (northern hemisphere) or lowest (southern) maximum point in the sky for the year before reversing
4 21 hours, 8 minutes in Reykjavik, Iceland
5 9 hours, 11 minute in Wellington, New Zealand
Answers