Math Riddles

 

Question: There are 100 coins scattered in a dark room. 90 have heads facing up and 10 are facing tails up. You cannot tell which coins are which. How do you sort the coins into two piles that contain the same number of tails up coins?


Question: You have 7 tennis balls that are all identical but one of them is slightly lighter than the others.

Using a balance scale and only two separate weightings, how can you find the light tennis ball?

Question: A farmer has three fields. One of them has 3 bundles of hay, another has 4, and the last has 5. How many would he have in the first field if he combined all of them in that field?

Question: If you have two twins, three triplets and four quadruplets; how many people do you have?

Question: There are two ropes that both take exactly 1 hour to burn from end to end. You are unable to cut the rope. How can you burn the two ropes in a total of 45 minutes?