# Puzzles

## Archive

Show me a random puzzle**Most recent collections**

#### Sunday Afternoon Maths LXVII

Coloured weightsNot Roman numerals

#### Advent calendar 2018

#### Sunday Afternoon Maths LXVI

Cryptic crossnumber #2#### Sunday Afternoon Maths LXV

Cryptic crossnumber #1Breaking Chocolate

Square and cube endings

List of all puzzles

## Tags

sport shape trigonometry dice scales crossnumbers factors dodecagons arrows doubling proportion factorials mean probabilty 2d shapes chocolate time cryptic crossnumbers chalkdust crossnumber indices probability remainders cards polygons money coins perimeter star numbers averages means pascal's triangle quadratics division fractions addition ellipses floors lines routes coordinates partitions odd numbers dates clocks digits cryptic clues spheres colouring multiples wordplay sums functions calculus symmetry hexagons geometry shapes complex numbers speed grids sequences advent planes 3d shapes people maths prime numbers circles parabolas square roots regular shapes games square numbers differentiation unit fractions balancing bases logic integration numbers rectangles folding tube maps chess ave books irreducible numbers surds angles taxicab geometry menace perfect numbers cube numbers graphs triangles sum to infinity crosswords algebra christmas rugby volume percentages integers palindromes multiplication number triangle numbers area squares## 2 December

In a week (Monday 12:01 to Monday 12:01 a week later), how many times will the minute hand of an analogue clock point in the same direction as the hour hand?

## Ticking clock

Is there a time of day when the hands of an analogue clock (one with a second hand that moves every second instead of moving continuously) will all be 120° apart?

## 8! minutes

How many weeks are there in 8! (\(8\times 7\times 6\times 5\times 4\times 3\times 2\times 1\)) minutes?

## Burning ropes

Source: Richard Wiseman's Blog

You have two ropes and some matches. Each rope, if lit at its end, will burn for 60 minutes. But the rate of burning is not regular, so cutting a rope in half doesn't result in a burn time of 30 minutes.

How can you use the ropes to time exactly 45 minutes?