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On the Road

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

There and Back

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

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?

Swimmers

Age 14 to 16
Challenge Level

  • Why wasn't the second crossing in the same place as the first?

  • If the swimmers can keep this going indefinitely will they have eventually had a crossing point everywhere along the length of the pool?

  • What happens if they both swim twice as fast?

  • What would happen if the pool was twice as long?



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.