mscroggs.co.uk
mscroggs.co.uk

subscribe

Puzzles

Burning ropes

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?

Show answer & extension

Tags: time
If you enjoyed this puzzle, check out Sunday Afternoon Maths I,
puzzles about time, or a random puzzle.

Archive

Show me a random puzzle
 Most recent collections 

Advent calendar 2023

Advent calendar 2022

Advent calendar 2021

Advent calendar 2020


List of all puzzles

Tags

square numbers determinants median crosswords the only crossnumber wordplay even numbers tiling integration digital products chalkdust crossnumber trigonometry axes sum to infinity digits triangle numbers pascal's triangle grids coordinates factors range cube numbers taxicab geometry hexagons lines digital clocks geometric mean unit fractions logic surds consecutive integers percentages division dice complex numbers mean sums bases products sequences multiplication remainders probability irreducible numbers colouring 2d shapes consecutive numbers averages area geometric means indices graphs floors rugby functions ave tournaments matrices advent albgebra shapes people maths integers balancing menace dominos geometry quadratics folding tube maps sport differentiation triangles christmas gerrymandering perimeter time probabilty speed planes dodecagons expansions coins elections crossnumbers chess multiples addition partitions books tangents 3d shapes shape routes prime numbers cryptic clues chocolate clocks number numbers arrows squares binary cryptic crossnumbers dates spheres polygons decahedra algebra games star numbers regular shapes parabolas factorials odd numbers quadrilaterals means money combinatorics cubics circles ellipses crossnumber symmetry calculus polynomials scales palindromes cards square roots proportion doubling angles rectangles volume pentagons fractions sets perfect numbers

Archive

Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2012–2024