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 

Sunday Afternoon Maths LXVII

Coloured weights
Not Roman numerals

Advent calendar 2018

Sunday Afternoon Maths LXVI

Cryptic crossnumber #2

Sunday Afternoon Maths LXV

Cryptic crossnumber #1
Breaking Chocolate
Square and cube endings

List of all puzzles


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


Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2019