Abook has a front and a back and 400 pages. the front and back cover are each 0.9mm thick measured to 1 decimal place. each page is 0.13 mm thick measured to 2 decimal places. calculate the minimum thickness of the book.

Front cover = Back cover = 0.9mm when round to the nearest tenth,
⇒ so the smallest possible number is 0.85mm

Front and Back cover =0.85 x 2 = 1.7mm

Each page is 0.13 when round to the nearest hundredth
⇒ so the smallest possible number is 0.125mm

400 pages = 0.125 x 400 = 50mm

Total thickness = 1.7+ 50 = 51.7mm

The minimum thickness is 51.7 mm.

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