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Tilted Tank

Age 11 to 14 Short Challenge Level:

A fish tank is a cuboid, 100 cm by 60 cm by 40 cm. It is partly filled with water, so that when it is resting on a 60 cm edge, the water level reaches the top edge and the midpoint of the base, as shown.


What will the height of the water be when the tank is resting on its base (a 100 cm by 60 cm face)?

This problem is adapted from the World Mathematics Championships
You can find more short problems, arranged by curriculum topic, in our short problems collection.