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On the Road

Four vehicles travelled on a road. What can you deduce from the times that they met?

Escalator

At Holborn underground station there is a very long escalator. Two people are in a hurry and so climb the escalator as it is moving upwards, thus adding their speed to that of the moving steps. ... How many steps are there on the escalator?

Illusion

A security camera, taking pictures each half a second, films a cyclist going by. In the film, the cyclist appears to go forward while the wheels appear to go backwards. Why?

There and Back

Age 14 to 16
Challenge Level

Brian swims at twice the speed that the river is flowing. He swims directly downstream, from one moored boat to another and then back again, taking 12 minutes altogether. How long would it have taken him in still water?

The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.
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NRICH is part of the family of activities in the Millennium Mathematics Project.