Math Riddles

Answer: He puts one plank across the corner of the square (where two sides meet) and puts the other perpendicular to it to form a 'T' shape in the corner allowing him to cross the moat and save his beloved.

Answer: 9. Two twins are 2 people, three triplets are 3 people, and four quadruplets are 4 people. 2 + 3 + 4 = 9.

Answer: He was 44 years old.

From the question you know the man died between 1900 and 1940. We also know his age at death (x) is one twenty-ninth of the year of his birth (29x). If you add his age at death to the year he was born you get the year he died (30x). Only one year between 1900 and 1940 is divisible by 30, 1920 (the year he died). The year he was born can now be found: 1920 * (29/30) = 1856. So in 1900 he was (1900 - 1856) = 44 years old.

Answer: The swan can travel 1/4 of the way to land then swim in a circular path around the center of the lake (the swan will be moving slightly faster around than the dog in their circles). Once the swan is as far as he can get away from the dog in his circle he can swim the remaining 3/4 of the way to shore. The dog must travel the radius of the lake time pi (radius * π) while the swan only has to travel 3/4 the radius four times slower (3/4 * radius * 4). So the swan will make it to the shore and fly before the dog reaches it.

Answer: All of the men (n) who are cheating will be killed and it will take one less than the number of cheating men nights (n-1) for their wives to discover this.

If one man was cheating, and that woman hadn't have heard of any other infidelity she would know it was her husband that was cheating. If there was two men cheating, both of their wives would think that since they have only heard of one man cheating he should die the next morning. If he doesn't die, she knows her husband must also be cheating and that's why the other husband didn't die. Following this logic, you can know that all of the men will die after one less night than there is cheating men.