Question 130333: The diameter of a toilet paper roll is 11cm, while the cardboard roll on the inside is 4cm. (Whole thing is 11cm, part without paper is 4cm in middle). Each piece of paper is 12cm by 12cm and the whole roll contains 240 sheets total. How many turns of the toilet paper is there and how thick is this toilet paper.
Answer by scott8148(6628)   (Show Source):
You can put this solution on YOUR website! the total length of the paper is 2880cm, 240*12cm
the mean, average, diameter is 7.5cm, (11cm+4cm)/2
so the paper will wrap around 2880/(7.5*pi) times __ this is the number of turns
the thickness of the paper is the thickness of the roll, (11cm-4cm)/2, divided by the number of turns
__ 3.5cm/(2880/(7.5*pi))
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