riddles and puzzles

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Last Updated: Wednesday, 01 January 2025 00:57

Published: Wednesday, 05 December 2018 20:45

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Riddles/puzzles:

1. Transport problem: There is a lion, cow and heap of grass. All 3 need to be transported from 1 side of river to other side on a boat. The boatman is rowing the boat, and he can only carry 1 of the 3 at one time, otherwise the boat will drown. Lion can eat cow, while cow can eat grass. Lion doesn't eat grass. How can the boatman transport all 3 of them across the river, without any of them eating anyone else. He can make as many trips as he wants. The only problem is that as soon as the boatman disappears from the scene, the animals are free to eat their food. So, if he leaves lion and cow while carrying grass with him, lion can eat cow. Since boatman cannot carry more than 1 of them with him, he has to leave 2 of them together, but in such a combination that no one can eat the other.

Soln: carry cow in 1st trip and leave it on other side of river. Then come back empty and carry lion with him. Then leave lion on other side, but bring back cow with him, else lion will eat cow. On his third trip, leave cow on the bank of river, and carry grass with him, and leave it on other side. Then come back empty, and carry cow with him to other side. Then all 3 animals end up on other side.

2. Switch problem: You have seen light switches in house. Sometimes we see the same light bulb being controlled by 2 switches. i.e light in the bedroom being controlled by the switch at entrance of bedroom, while also being controlled by switch by the side of bed. Draw a connection diagram showing how it works. We will need 3 way switch for these, not the regular 2 way switch. Also, how can you control the light bulb with "n" switches. We will need 4 way switches to make this work.

3. Bulb Problem: 3 incandescent bulbs in a closed room, 3 switches outside the room. All switches are in off state to start with, so all light bulbs are off. How can you figure out which light bulb is controlled by which switch. You are allowed to turn switches on/off as many times as you want, but once you enter the room, you are not allowed to go outside the room and flip switches again.

4. monty hall problem: Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice? 

5. Hardest Logic puzzle: Logic puzzles are yes/no questions to derive an answer. Link to Hardest Logic Puzzle => https://en.wikipedia.org/wiki/The_Hardest_Logic_Puzzle_Ever

• A simpler version of this puzzle for kids is as follows (the answer is in link above) => You are standing before two doors. One of the path leads to heaven and the other one leads to hell. There are two guardians, one by each door. You know one of them always tells the truth and the other always lies, but you don’t know who is the honest one and who is the liar. You can only ask one question to one of them in order to find the way to heaven. What is the question?

Kids Maths:

1. If there are 4 apples and you take away 3, how many do you have? => 3, because you took 3

2. What occurs twice in a week, once in a year but never in a day? => letter e

3. What goes up and doesn’t come back down?

4. What has two hands but no legs? => clock

5. What’s the easiest way to double your money? => in front of mirror

6. Which month has 28 days? => all of them

7. If four men can build four tables in four hours, how many tables can eight men build in eight hours? =>

8. Three guys rent a hotel room for the night. When they get to the hotel they pay the $$\$30 $$ fee, then go up to their room. Soon the bellhop brings up their bags and gives the lawyers back $5 because the hotel was having a special discount that weekend. So the three lawyers decide to each keep one of the $5 dollars and to give the bellhop a $2 tip. However, when they sat down to tally up their expenses for the weekend the could not explain the following details:
Each one of them had originally paid $10 (towards the initial $30), then each got back $1 which meant that they each paid $9. Then they gave the bellhop a $2 tip. HOWEVER, 3 • $9 + $2 = $29
The guys couldn't figure out what happened to the other dollar. After all, the three paid out $30 but could only account for $29. Can you determine what happened?

9. What digit is the most frequent between the numbers 1 and 1,000 (inclusive)? To solve this riddle you don't want to manually do all of the math but rather try to figure out a pattern.

10. How can you add eight 8's to get the number 1,000? (only use addition) => 888+88+8+8+8

11. Jammy is a milkman. He has 3-liter and 5-liter milk cans. Now, he want to measure 4 liters from these milk cans. How can he do it? =>