Colliding parallel people

If two people stand 1km apart and walk in the same direction, how far will the have to walk until they collide due to the curvature of the Earth? (diameter of Earth = 12,742km)

Show answer & extension

If you enjoyed this puzzle, check out Sunday Afternoon Maths III,
puzzles about 3d shapes, or a random puzzle.


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


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


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