Brain Teasers 9 - Puzzle Prime

You are chasing a criminal riding a bicycle, and you find his tracks left in the dirt. By investigating the tracks, can you determine which direction the criminal has fled to: left or right?

SOLUTION

The front wheels of the bicycle are traveling more distance and making sharper turns. Thus, the red tracks (as shown on the image below) correspond to the front wheel, and the green tracks correspond to the back wheel.

Then, since the back wheel is always pointing towards the front wheel, we conclude that the bicycle is moving towards the right.

Unknown Author March 16, 2023

2 Comments

STANDARD Word

Section: Brain Teasers Category: Insight

Difficulty: Hard

Given the word STANDARD, take away two letters and then add three digits to make a logical sequence.

SOLUTION

Remove the two letters A to get ST-ND-RD and then add the digits 1, 2, 3 to get 1ST-2ND-3RD.

Unknown Author March 7, 2023

0 Comments

Toasting Bread

Section: Brain Teasers Category: Deduction

Difficulty: Medium

Your toaster is broken, so you decide to toast your bread in a pan. The pan can hold three slices of bread at a time and takes 1 minute to toast one of their sides. How much time would it take you to toast four slices of bread on both sides using the pan?

SOLUTION

It would take you 2 minutes and 40 seconds. Label the slices with A, B, C, D, their top sides A1, B1, C1, D1, and their bottom sides A2, B2, C2, D2.

Toast A1, B1, C1 for 40 seconds.
Toast A2, B2, D1 for 40 seconds.
Toast A1, C2, D2 for 20 seconds.
Toast A2, C2, D2 for 20 seconds.
Toast B1, C1, D1 for 20 seconds.
Toast B2, C2, D2 for 20 seconds.

Unknown Author March 1, 2023

0 Comments

100 Guests in 99 Rooms

Section: Brain Teasers Category: Deduction

Difficulty: Easy

One hundred people entered a hotel that had 99 rooms, and each of them asked for their own room. In order to solve the problem, the bellboy did the following:

He asked the 100th guest to wait for a while with the 1st guest in room number 1, so that there were 2 guests inside. Then he took the 3rd guest to room number 2, the 4th guest to room number 3, and so on, until finally taking the 99th guest to room number 98. At the end he returned to room number 1 and took the 100th guest to room number 99, which was still vacant.

How could everybody get their own room?

SOLUTION

The two people who were taken to room number 1 were guest 1 and guest 100. Thus, the 2nd guest ended up without a room.

Unknown Author February 22, 2023

2 Comments

Died on the Fourth of July

Section: Brain Teasers Category: Deduction

Difficulty: Medium

During a trivia night, the following question appeared:

“Among the first five US presidents, Washington, Adams, Jefferson, Madison, and Monroe, there were 3 who died on the fourth of July. Can you guess which ones?”

After nobody answered the question, the following hint was given:

“These three presidents were consecutive ones.”

Then, all contestants immediately managed to answer the question. Can you?

SOLUTION

Because of the way the question was worded, it was clear that the fifth president, James Monroe, was one of them. Otherwise, the trivia question would have been “among the first four US presidents” instead of “among the first five”. Since the three presidents that died on fourth of July were consecutive ones, they were Jefferson, Madison, and Monroe.

Unknown Author February 16, 2023

2 Comments

Limbs

Section: Brain Teasers Category: Deduction

Difficulty: Advanced

Partition the grid into disjoint “creatures”, according to the following rules:

Each creature is defined as a shape of 4 connected branches that are each 1 cell wide.
For each creature, one of the branches ends up with a HEAD (always clued) and the other three branches end up with LIMBS (whenever clued, their directions matter).
A creature can never occupy a 2×2 region of cells and can never touch itself.

Examine the first example, then solve the other three puzzles.