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

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

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?

If 12 cattle eat up 3 1/3 acres of meadow in 4 weeks and 21 cattle eat up 10 acres of exactly similar meadow in 9 weeks, how many cattle shall eat up 36 acres in 18 weeks? (Hint: The grass continues to grow.)

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.

If a ball 6 inches in diameter weighs 32 lbs, what will be the weight of a ball 3 inches in diameter?

Find the two numbers such that multiplying one by the other makes 8 and the sum of their squares is 27

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...

How high above the earth must a person be raised that he [or she] may see 1/3 of its surface?