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N Is a Number
Age 11 to 14
Challenge Level 
Why do this problem?
This problem, which does not need the use of algebra, is nevertheless, quite tricky to do and does require clear logical thinking. Learners will need to understand the properties of numbers and the relationships between speed, time and distance.Key questions
Is N odd or even?
What sort of speed would you expect the walkers to do?
How long do the walkers take to reach B?
How large can N be?
How many minutes are there in an hour? Does this make a
difference?
How can the distance of road be related to the speed of car
and the time taken travelling?
Possible extension
Learners who found this problem easy could try Four on the Road.Possible support
Suggest trying Bike Ride which is an easier problem instead.You may also like
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A paradox is a statement that seems to be both untrue and true at the same time. This article looks at a few examples and challenges you to investigate them for yourself.