Can you make a tetrahedron whose faces all have the same perimeter?
Three circular medallions fit in a rectangular box. Can you find the radius of the largest one?
Is the mean of the squares of two numbers greater than, or less
than, the square of their means?
Rudolff's book, called Coss, written in 1525, was the first German algebra book. The reason for the title is that cosa is a 'thing', a term used for the unknown. Algebraists were called cossists, and algebra the cossic art, for many years. Here is the problem:
A group of 20 people pay a total of £20 to see an exhibition. The admission price is £3 for men, £ 2 for women and 50p for children. How many men, women and children are there in the group?