Logic Riddles

Answer: Here are the two solutions. This is usually solved with guess and check although using logic may be faster. We know that each queen must be in it's own row vertically and horizontally. We also know that 4 of the queens must be on white and 4 on black. This is true because with 4 queens on the same color all of the rest of that color is venerable to attack. (It could be done with math).

Answer: 43.

After 6 all numbers divisible by 3 can be ordered (because they can all be expressed as a sum of 6's and 9's). After 26, all numbers divisible by three when subtracted by 20 can be obtained. After 46, all numbers divisible by three when subtracted by 40 can be obtained. After 46, all numbers fit into one of these 3 categories, so all numbers can be obtained. 43 is the last number that doesn't fall into one of these categories (44 = 20 + 6 * 4, 45 = 6 * 6 + 9).

Answer: If they are round the manhole covers cannot slip into the hole if the hole is slightly smaller than the cover, but if they are square the hole would have to be about 50 percent of the area of the cover to stop the cover from falling into the hole (diagonally).

Answer: The four men are musicians getting payed to play.

Answer: None, Noah built the ark, not Moses.