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Weekly Problem 12 - 2006

Stage: 4 Challenge Level: Challenge Level:1

A van travels from Newcastle to South Shields at an average speed of $30$ mph and returns by the same route at an average speed of $40$ mph. What is the van's average speed for the whole journey?
 
If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.  

This problem is taken from the UKMT Mathematical Challenges.

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