Top Math Riddles with Answers
An interesting formula for generating a good many (but not all) primes is n2 + n + 41. If we plug in consecutive integers 1, 2, 3, etc., at least up to a certain point, we can generate prime numbers. Give an integer for which the formula fails.
In a pond there are some flowers with some bees hovering over the flowers. How many flowers and bees are there if both the following statements are true: 1. If each bee lands on a flower, one bee doesn't get a flower. 2. If two bees share each flower there is one flower left out.
Cathy has six pairs of black gloves and six pairs of brown gloves in her drawer. In complete darkness, how many gloves must she take from the drawer in order to be sure to get a pair that match? (a left and right glove of the same color)
There is a party of 100 high-powered politicians. All of them are either honest or liars. You walk in knowing two things:
- At least one of them is honest.
- If you take any two politicians, at least one of them is a liar.
From this information, can you know how many are liars and how many are honest?
What is the largest possible number you can write using only 2 numbers - just 2 numbers, no other mathematical symbols?
There are several books on a bookshelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?
There has just been a heavy snowfall, Jeff goes out side and finds that there is twice as much snow in his garden as his neighbor's Kate but Jeff doesn't seem surprised.Why?
There is a clothing store in Bartlesville. The owner has devised his own method of pricing items. A vest costs $20, socks cost $25, a tie costs $15 and a blouse costs $30. Using the method, how much would a pair of underwear cost?
You want to boil a two-minute egg. If you only have a three-minute timer (hourglass), a four-minute timer and a five-minute timer can you boil the egg for only two minutes?
How can you distribute three apples to two fathers and their two sons, giving a whole apple to each.
Three matches are sitting on a table. Without adding another make the three matches four. You are not allowed to break any of the matches.
My only timepiece is a wall clock. One day I forgot to wind it and it stopped. I went to visit a friend who has a watch which is always correct, stayed a while, and then went home. There I made a simple calculation and set the clock right.
How did I do this even though I had no watch on me to tell how long it took me to return from my friend's house?
If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door.
A man is considering how quickly his life has flown by.
He thinks to himself, “the day before yesterday I was 37, and next year I will be 40!”
The man has made no error in his calculation. On what day of the year is his birthday?
100 passengers are boarding a plane with 100 seats. The first passenger in line has lost his boarding pass and chooses a random seat to sit in. Each subsequent passenger takes their assigned seat if it is unoccupied. Otherwise, they take a random unoccupied seat.
What is the probability that the last passenger will find their seat unoccupied?