#02 Getting past the freight train
A very long passenger train is heading along a single track railway behind a freight train composed of a locomotive and three freight trucks. They are approaching a station where the freight train is due to unload. To keep to its timetable, the passenger train needs to leave before the freight train will have had time to unload.
At the station, there is a siding that either train could drive into. The siding is large enough to hold a locomotive and one freight truck, or two freight trucks. Both trains have couplings at the front that allow them to push and pull trucks.
How can the passenger train get past the freight train so that both can continue on their journey?
Answer next week
#01 The book of numbers Solution
Last week, we asked you for the second and second to last numbers in a book listing all the whole numbers from zero to infinity in alphabetical order.
The second number is 8,000,000,000 (eight billion). The second last is 2,000,000,002,202 (two trillion two thousand two hundred and two).
Quick quiz #02
1 What is the name given to an irrational number written, for example, as 鈭�2 to express its exact value without all its digits?
2 In what southern German city was Albert Einstein born?
3 Known also as aqua fortis, what acid was used in the original acid test, and to do what?
4 Described as a 鈥渨ildlife wonder of the world鈥�, the 3-hectare Bass Rock off the north-east coast of the UK is home to the world鈥檚 largest colony of which seabird, numbering some 150,000?
5 Developed by the US National Center for Supercomputing Applications and released in 1993, what was the first widely available graphical web browser called?
Answers below
Answers
1. A surd
2. Ulm
3. Nitric acid, to distinguish gold from other metals
4. The northern gannet. Its formal name, Morus bassanus, derives from the rock
5. Mosaic
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Article amended on 20 May 2019
We corrected the second-last number in the book of numbers solution