Hard Riddles

Hard riddles with answers are a true test of your brain power, reasoning and comprehension. You are sure to find these tough difficult riddles both challenging and puzzling. While these hard riddles and answers may drive you a little crazy sometimes, they may surprise you in the way they force you think out of the box.

10 Bottles 100 Pills

There are 10 identical bottles of identical pills. Each bottle contains 100 pills. Out of 10 bottles 9 have 1 gram of pills but 1 bottle has pills of 1.1 gram in weight. Given a measurement scale, how would you find the heavy bottle? You can use the scale only once.

Riddle Answer

Two Mathematicians and a Coin

The king is very angry at his two best mathematicians, so he decrees the following punishment:

The mathematicians will be imprisoned in towers at opposite ends of the kingdom. Each morning, a guard at each tower will flip a coin and show the result to his prisoner. Each prisoner must then guess the result of the coin flip at the other tower. If at least one of the two guesses is correct, they will live another day. But as soon as both guesses are incorrect, they will be executed.

The two mathematicians, as they were being ushered out the door of the castle, came up with a clever plan so that they will always be able to make at least one correct guess. What was their plan?

Riddle Answer