NRICH: Warmsnug Double Glazing

How have “Warmsnug” arrived at the prices shown on their windows? Which window has been given an incorrect price?

Warmsnug calculate the prices of their windows according to the area of glass used and the length of frame needed.

Can you work out how Warmsnug arrived at the prices of the windows below?
Which window has been given an incorrect price?


This spreadsheet generates prices for the windows according to different pricing rules.
Can you find an efficient strategy for finding how the prices were calculated?

Age 14 to 16

Algebra & Pre-Algebra, Equations
High School, Educator

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NRICH (University of Cambridge)

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PDF File

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The information is available on a printable worksheet here.