Stage: 4 Challenge Level: 
My train left London between 6 a.m. and 7 a.m. and arrived in Paris between 9 a.m. and 10 a.m. I noticed that at the start and end of the journey the hands on my watch were in exactly the same positions but that the minute hand and hour hand had swopped places. What time exactly did the train leave London and how long did the journey take?
Manipulating algebraic expressions/formulae. Reflections. Other equations. Angles. Complex numbers. Rotations. Symmetry. Time. Creating expressions/formulae. Mathematical reasoning & proof.
Published March 1999.
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