Sunday Afternoon Maths LV


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 Posted on 2016-10-16 

Blackboard Sums

The numbers 1 to 20 are written on a blackboard. Each turn, you may erase two numbers, \(a\) and \(b\) and write the sum \(a+b\) in their place. You continue until only one number remains.
What is the largest number you can make?

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Tags: numbers

Two Tangents

Source: Reddit
Find a line which is tangent to the curve \(y=x^4-4x^3\) at 2 points.

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Powerful Quadratics

Source: nrich
Find all real solutions to

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If you enjoyed this puzzle, check out Sunday Afternoon Maths LXII,
puzzles about cube numbers, or a random puzzle.
© Matthew Scroggs 2018