entertainment beginner 10 sample questions

Brainteaser MCQ Practice Test

A type of puzzle that requires creative or lateral thinking to solve, often involving riddles or logic tricks.

Q1. In a certain puzzle, there are 3 switches, but they are not labelled. Each switch corresponds to one of three light bulbs in a room. Each light bulb is off at the start. You can turn the lights on and off as many times as you want, but you can only enter the room one time. How can you figure out which switch corresponds to which light bulb?

A. Create a pattern of switching the lights on and off to determine the correct switch.
B. Turn two of the switches on for a few minutes, then turn them off and enter the room to observe the bulbs. ✓
C. Flip all three switches on, then enter the room to see which bulbs are on.
D. Count the number of bulbs that are on, then try each switch to see which one corresponds to the correct number of bulbs.

Explanation: This solution works because when you turn two of the switches on, the corresponding bulbs will be hot, even if they are turned off when you enter the room. By observing the bulbs, you can determine which switch corresponds to which light bulb.

Q2. In a 3x3 grid, a snail is at the bottom left corner. It can move either right or up at any time. How many paths can the snail take to reach the top right corner?

A. 6
B. 12 ✓
C. 20
D. 30

Explanation: The snail has to make 4 moves to reach the top right corner. It can move right 2 times and up 2 times. The order of these moves can be any of the 4 moves. We can calculate the number of paths using the formula 4! / (2! * 2!) which is equal to 12.

Q3. You have 3 switches, but they are not labelled. 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. How can you figure out which switch corresponds to which light bulb?

A. Turn all switches on for 5 minutes, then turn two of them off and enter the room.
B. Turn switch 1 on for 5 minutes, then turn it off and turn switch 2 on. Enter the room and feel the light bulbs to determine which one is hot.
C. Turn switch 1 on for 5 minutes, then turn it off. Turn switch 2 on for 5 minutes, then turn it off. Turn switch 3 on and enter the room. ✓
D. Use a flashlight to examine the light bulbs in the room before turning any switches on.

Explanation: This solution works because you can use the heat of the light bulbs to determine which switch corresponds to which light bulb. After turning switch 1 on for 5 minutes, the first light bulb will be hot. Then, after turning it off and turning switch 2 on, the second light bulb will be hot. Finally, after turning switch 3 on, the third light bulb will be hot.

Q4. You have 8 balls, and one of them is slightly heavier or lighter than the others. How can you find the heavier or lighter ball in only 2 weighings on a balance scale?

A. Weigh 3 balls against 3 balls, then weigh the remaining 2 balls against each other.
B. Weigh 3 balls against 3 balls, then weigh the heavier or lighter side against the remaining 2 balls. ✓
C. Weigh 4 balls against 4 balls, then weigh the remaining 2 balls against each other.
D. Weigh 5 balls against 5 balls, then weigh the remaining 3 balls against each other.

Explanation: This solution works by using the process of elimination. In the first weighing, if the two sides are balanced, the heavier or lighter ball is among the 4 balls not on the scale. In the second weighing, if the heavier or lighter side is weighed against one of the remaining 2 balls, it will balance if the ball on the scale is the heavier or lighter one, and it will not balance if the ball on the scale is one of the other 3 balls.

Q5. In a room with three light switches, but no light bulbs in the room. Each switch corresponds to one of the 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. How can you figure out which switch corresponds to which light bulb?

A. Turn switch 1 on for 5 minutes, then turn it off and turn switch 2 on. Enter the room and look for the hot light bulb.
B. Turn switch 1 on, then turn it off. Turn switch 2 on, then turn it off. Turn switch 3 on and enter the room.
C. Turn switch 1 on for 5 minutes, then turn it off. Turn switch 2 on for 5 minutes, then turn it off. Turn switch 3 on and enter the room. ✓
D. Turn switch 1 on, then turn it off. Turn switch 2 on and leave it on. Turn switch 3 on and enter the room.

Explanation: This puzzle requires you to use the switches to create a situation where you can determine which switch corresponds to which light bulb. By turning switch 1 on for 5 minutes and then turning it off, you can tell if the corresponding light bulb is hot or not. Then, by turning switch 2 on for 5 minutes and then turning it off, you can tell if the corresponding light bulb is hot or not. Finally, by turning switch 3 on and entering the room, you can see which light bulb is on, and therefore which switch corresponds to which light bulb.

Q6. A “River Crossing” puzzle has 5 people: a brunette, a blonde, a priest, a doctor, and a lawyer. The brunette can't be in the same boat as the priest, the blonde can't be in the same boat as the lawyer, and the doctor can't be in the same boat as the brunette. Each person must cross the river, and each boat can hold only 2 people. What is the minimum number of trips required for all 5 people to cross the river?

A. 3 trips
B. 4 trips ✓
C. 5 trips
D. 6 trips

Explanation: To solve this, pair the brunette with the doctor (since the doctor can't be with the brunette) and send them across first. Then, the priest and the blonde can cross together. Next, the brunette and the doctor can return. Finally, the lawyer and the priest can cross together. This sequence requires 4 trips.

Q7. A “Hacker’s Delight” puzzle states: “A bat and a ball together cost $1.10. The bat costs $1.00 more than the ball. How much does the ball cost?” What is the name of the mathematician who first proposed this puzzle?

A. Albert Einstein
B. Pierre de Fermat
C. Paul Erdös
D. Lewis Carroll ✓

Explanation: The puzzle is attributed to Lewis Carroll, a mathematician and logician who is best known for his work on logic and his writing of Alice's Adventures in Wonderland. The puzzle is a classic example of a lateral thinking puzzle, which requires the solver to think creatively and consider alternative solutions.

Q8. In the classic 15 Puzzle, a 4x4 grid of tiles numbered 1-15 and one empty space, what is the maximum number of moves required to solve the puzzle if the initial configuration is a random permutation of the tiles, and the empty space is initially in the bottom-right corner?

A. 31 moves
B. 70 moves
C. 80 moves ✓
D. 100 moves

Explanation: The maximum number of moves required to solve the 15 puzzle is 80 moves. The empty space's initial position does not directly affect the maximum number of moves. The number of moves depends on the initial configuration's parity, and the worst-case scenario requires 80 moves.

Q9. A finite number of people are standing in a line, and each person has exactly 3 coins. At regular intervals, each person in the line will pay 1 coin to the person in front of them. If the person at the front of the line has 0 coins left, the line will freeze. If the person at the front of the line has more than 3 coins left, the line will start moving again. The line will freeze after the number of coins transferred is a multiple of #61 but not a multiple of #64. What is the smallest possible number of people in the line?

A. It is a multiple of 61 but not a multiple of 64 ✓
B. It is a multiple of 64 but not a multiple of 66
C. It is a multiple of 66 but not a multiple of 68
D. It is a multiple of 68

Explanation: This puzzle involves a sequence of coins being transferred between people in a line. The key to solving this puzzle is to realize that the number of coins transferred is a multiple of 61 but not a multiple of 64, which means that the line will freeze after a multiple of 61 coins have been transferred, but not after a multiple of 64 coins have been transferred.

Q10. A farmer has 10 sheep, but one of them is a black sheep. If he places a red hat on one of the 9 white sheep, and you don't know which one, then you don't know which sheep is the black sheep. However, if he places a blue hat on one of the 9 white sheep, and you can see that the black sheep is standing next to a sheep wearing a blue hat, then you can figure out which sheep is the black sheep. How can you figure out which sheep is the black sheep if the farmer puts 5 red hats and 4 blue hats on the 9 white sheep?

A. You can't figure out which sheep is the black sheep.
B. You can figure it out by counting the number of red hats.
C. You can figure it out by counting the number of blue hats.
D. You can figure it out by counting the number of white hats adjacent to blue hats. ✓

Explanation: The solution is to count the number of white hats adjacent to blue hats. Since there are 5 red hats, there must be 4 white hats adjacent to blue hats, and the black sheep is the one standing next to a white hat that is not adjacent to a blue hat.

That was just a sample. Sign up to unlock the full question bank with timed tests and certificates.