For hundreds of years, it was accepted in international law that the territorial waters of any country extended three miles from the shore.
The knapsack problem is a simple example of a type of "integer programming" problem which is frequently met in the field of mathematics known as Operations Research.
The new format of the 4-unit paper contains provisions for a number of harder questions on the 3-unit syllabus, as well as questions on the 4-unit material.
I have recently discovered a diversion which may be of interest to readers.
We received a letter from Catherine Playoust, aged 12
Q.515 I have two different integers $> 1$. I inform Sam and Pam of this fact and I tell Sam the sum of my two numbers and I tell Pam their product. The following dialogue then occurs:
Q.491 Find a four digit number which becomes nine times as large if the order of digits is reversed.