A California miner has a spherical ball of gold, 2 inches in diamter, which he wants to exchange for spherical balls 1 inch in diameter. How many of the smaller spheres should he receive?

Individual problems from throughout mathematics history, as well as articles that include problem sets for students.

The sum of two numbers is 10 and their product is 40. What are the numbers?

A railway train strikes a snowdrift which creates a constant resistance. How long does it take the snow to stop the train?

One military horse cannot pull a load of 40 dan; neither can 2 ordinary horses, nor can three inferior horses.

In baking a hemispherical loaf of bread of 10" radius, the crust was everywhere of an equal thickness, and the solidity of the crust was equal to half the solid content of the whole loaf. What were the dimensions of the interior soft part?

Given a triangular piece of land having two sides 10 yards in length and its base 12 yards, what is the largest square that can be constructed within this piece of land so that one of its sides lies along the base of the triangle?

Three men have a pile of money, their shares being 1/2, 1/3 and 1/6. Each man takes some money from the pile until nothing is left.

A person has a circular yard that is 150 ft. in diameter, and wishes a walk of equal width made round it within the fence...

What is the sum of the following series, carried to infinity: 11, 11/7, 11/49, etc.?

Suppose that the propability of success in an experiment is 1/10. How many trials of the experiment are necessary to insure even odds on it happening at least once?