7 Maths Brain Teasers to Test Your Logic

Challenge Your Mind with These 7 Maths Brain Teasers

Maths brain teasers are an excellent way to test your logical thinking and problem-solving skills. They require you to think creatively and approach problems from different angles. Here are 7 maths brain teasers to challenge your mind and keep your logical thinking sharp.

Brain Teaser 1: The Three Switches

You are standing in a room with three light switches. Each switch corresponds to one of three light bulbs in a room. Each light bulb is either on or off. You can turn the lights on and off as many times as you want, but you can only enter the room one time to observe the light bulbs. How can you figure out which switch corresponds to which light bulb?

💡 Note: You can only enter the room once, so think carefully about your strategy.

Brain Teaser 2: The Five Hats

Five people are wearing hats, and each hat is either black or white. Each person can see the hats of the other four people, but not their own. How can the people figure out what color their own hat is?

• Each person can ask one question to one other person.
• The question can only be "Is your hat black or white?"

Brain Teaser 3: The Water Bottles

You have three water bottles, one that holds 3 litres, one that holds 5 litres, and one that holds 8 litres. How can you measure out exactly 4 litres of water using only these three bottles?

Brain Teaser 4: The Mysterious Temple

You are standing in front of a mysterious temple with two doors. One door leads to certain death, and the other door leads to freedom. However, the doors are identical, and there is no label or sign on either door. There is a guard standing in front of each door. One guard always tells the truth, and the other guard always lies. You don’t know which guard is which or which door leads to freedom. You can ask one question to one guard. What question should you ask to ensure you choose the door to freedom?

Brain Teaser 5: The Number Sequence

Look at the following number sequence: 1, 2, 4, 7, 11,?. What comes next in the sequence?

Brain Teaser 6: The Age Problem

A mother is three times older than her son. In 12 years, the mother will be twice as old as her son. What is the mother’s current age?

Brain Teaser 7: The Counterfeit Coin

You have eight coins, and one of them is counterfeit. The counterfeit coin weighs slightly less than the real coins. How can you use a balance scale and only two weighings to determine which coin is counterfeit?

Now, take your time to think about each brain teaser and see if you can come up with a solution. Good luck!

After trying to solve these brain teasers, you can check the answers below.

Answers

Brain Teaser 1: The Three Switches

Turn switch 1 to the “on” position for 5 minutes. Then, turn switch 1 to the “off” position and turn switch 2 to the “on” position. Enter the room and observe the light bulbs. If a light bulb is on, it corresponds to switch 2. If a light bulb is off, but warm, it corresponds to switch 1. If a light bulb is off and cold, it corresponds to switch 3.

Brain Teaser 2: The Five Hats

Each person asks one other person if their hat is black or white. If a person sees four white hats, they know their own hat is black. If a person sees four black hats, they know their own hat is white. If a person sees a mix of black and white hats, they don’t know their own hat color. However, they can ask the person with the opposite hat color if their hat is black or white. If that person says yes, they know their own hat color.

Brain Teaser 3: The Water Bottles

Fill the 8-litre bottle completely. Pour water from the 8-litre bottle into the 5-litre bottle until the 5-litre bottle is full, leaving 3 litres in the 8-litre bottle. Empty the 5-litre bottle and fill it with the remaining 3 litres from the 8-litre bottle. Fill the 8-litre bottle again and pour water from the 8-litre bottle into the 5-litre bottle until the 5-litre bottle is full, which will leave 4 litres in the 8-litre bottle.

Brain Teaser 4: The Mysterious Temple

Ask one of the guards, “If I were to ask the other guard which door leads to freedom, what would they say?” Think about it for a moment. If you ask the truth-telling guard, they will tell you that the lying guard would point to the door that leads to death. If you ask the lying guard, they will lie about what the truth-telling guard would say, so they will also point to the door that leads to death. Therefore, you can safely assume the opposite door leads to freedom.

Brain Teaser 5: The Number Sequence

The pattern is obtained by adding 1, 2, 3, 4, and so on to the previous term. Therefore, the next number in the sequence is 1 + 2 + 3 + 4 + 5 + 6 = 16 + 1 = 17.

Brain Teaser 6: The Age Problem

Let’s say the son’s current age is x. Then, the mother’s current age is 3x. In 12 years, the son’s age will be x + 12, and the mother’s age will be 3x + 12. According to the problem, the mother will be twice as old as her son in 12 years, so 3x + 12 = 2(x + 12). Solve for x to get x = 12. Therefore, the mother’s current age is 3x = 36.

Brain Teaser 7: The Counterfeit Coin

Weigh four coins against four coins. If one side is heavier, the counterfeit coin is one of those four. If the two sides are balanced, the counterfeit coin is one of the remaining four. Take the four coins that may contain the counterfeit coin and weigh three of them against each other. If one is lighter, it’s the counterfeit coin. If they are balanced, the remaining coin is the counterfeit one.

You Made It!

I hope you enjoyed these maths brain teasers and had fun challenging your logical thinking. Remember, practice makes perfect, so keep practicing and you’ll become a master of logical reasoning.