You have 20 buckets of blocks, a knife, and a weighing scale. Each bucket has 100 blocks. 19 of the buckets have blocks that weigh 16oz each, and one bucket has blocks that weigh 17oz each. How do you figure out which bucket has the 17oz blocks by weighing only once?
Riddle AnswerHard Riddles
Three Spies
Three spies, suspected as double agents, speak as follows when questioned:
Albert: “Bertie is a mole.”
Bertie: “Cedric is a mole.”
Cedric: “Bertie is lying.”
Assuming that moles lie, other agents tell the truth, and there is just one mole among the three, who is the mole?
Riddle Answer3 Sacks of 30 Coconuts
An intelligent trader travels from one place to another with 3 sacks having 30 coconuts each. No sack can hold more than 30 coconuts. On the way, he passes 30 check points. At each check point, he has to give one coconut for every sack he is carrying. What is the maximum number of coconuts that he can have with him at the end of his journey?
Riddle AnswerMr Tan’s Birthday
Ben and Mark are students of Mr Tan. Mr Tan’s date of birth is on N/M/1970 and both of them know that Mr Tan’s birthday is one of these 10 dates:
4/3/1970 5/3/1970 8/3/1970 4/6/1970 7/6/1970 1/9/1970 5/9/1970 1/12/1970 2/12/1970 8/12/1970
Mr Tan tells Ben the value of M and tells Mark the value of N. Then Mr Tan asks them: “Do you know when my birthday is?”
Ben says: “I don’t know, but I can be sure that Mark doesn’t know either.”
Mark says: “Initially I don’t know, but now I do.”
Ben says: “Oh, then now I know it too.”
Based on this dialogue and the dates given, can you figure out which is the correct date of Mr Tan’s birthday?
Riddle AnswerFlashlight and 8 Batteries
You have 8 batteries (4 charged batteries, 4 uncharged batteries) and a flashlight which needs 2 charged batteries to work.
You do not know which batteries are charged and which ones are uncharged. What is the least number of attempts to make the flashlight work? (An attempt consists of putting two batteries in the flashlight and checking if the flashlight works or not.)
Riddle Answer