2 December

What is the maximum number of lines that can be formed by the intersection of 30 planes?

Two lines

Let A and B be two straight lines such that the gradient of A is the y-intercept of B and the y-intercept of A is the gradient of B (the gradient and y-intercept of A are not the same). What are the co-ordinates of the point where the lines meet?

Show answer & extension


Show me a random puzzle
 Most recent collections 

Advent calendar 2019

Sunday Afternoon Maths LXVII

Coloured weights
Not Roman numerals

Advent calendar 2018

Sunday Afternoon Maths LXVI

Cryptic crossnumber #2

List of all puzzles


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


Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2012–2020