Articles of puzzle

Maths brain teaser. Fifty minutes ago it was four times as many minutes past three o'clock

Fifty minutes ago it was four times as many minutes past three o’clock. How many minutes is it to six o’clock..? I have got the solution online but have doubts in it : There are 180 minutes between 3 o’clock and 6 o’clock. Call x the number of minutes to 6 o’clock. Then it is […]

Weights – Objects into bags puzzle

I found a maths puzzle somewhere and a part of it as below: Kelly wants to place n objects $a_1 , a_2 , ··· , a_n$ into $k > 1$ bags. For each $i = 1 , 2 , ··· , n $, the weight of $a_i$ is $w_i$ kilograms. The capacity of each bag […]

Is this urn puzzle solvable?

Sent to me by a friend, I’m stumped. We have an urn. It is first filled with balls of $C$ different colors, ${N_1,N_2,…N_c}$ of each of the colors. Lastly, a ball with a distinct marking is added. We are not given $C$ or any of the $N$ values. A machine removes the balls without replacement […]

Simple Logical reasoning question

I am trying to improve my logical reasoning skills. Came across below question. See image. Can anybody let me know what the logical reasoning to the answer will be. I have no idea how to solve this The question is, “Which of diagrams A, B, C, D, or E is the best continuation of the […]

Very fascinating probability game about maximising greed?

Two people play a mathematical game. Each person chooses a number between 1 and 100 inclusive, with both numbers revealed at the same time. The person who has a smaller number will keep their number value while the person who has a larger number will halve their number value. Disregard any draws. For example, if […]

Square covered with tiles

A square $666\times666$ has been covered using tiles $5\times1$. A single square $1\times 1$ hasn’t been covered. Find in how many places the not covered square can be.

Expected Value of the Difference between 2 Dice

What is the expected value of the absolute difference between 2 N faced dice? What about the difference between 2 dice one with N faces and one with M faces? While finding the expected value of 2 random variable sums or differences are simple enough, how do you deal with absolute value of differences? Thanks

How to efficiently generate a set uniformly distributed numbers that add to $n$.

I am in need of a more generalized solution to this problem. I have a random number generator that generates numbers from 0 to 1. Using this, I want to find $r$ numbers that add to $n$. How do I do this efficiently, and such that the numbers are uniformly distributed? For my specific case, […]

Probability in Minesweeper

Suppose I click a random tile during a Minesweeper game. It is a 1. During each time I click an adjacent square, what are the chances of hitting a mine? How would this change if it were a 2 or another number?

Decomposing a circle into similar pieces

Is it possible to decompose a circle into finitely many similar disjoint pieces, one of which contains the circle’s center in its interior?