A metal cylinder with height $10\;cm$ and the diameter of base $70\;cm$ is melted to make a number of small discs with radius $1\;cm$ and thickness $0.5\;cm$. How many such discs could be made from the cylinder?

Using the volume conservation principle, the volume of the large cylinder equals the total volume of the small discs. The volume of the cylinder is pi * 35^2 * 10, which equals 12250 * pi. The volume of one small disc is pi * 1^2 * 0.5, which equals 0.5 * pi. Dividing the total volume by the volume of one disc gives 12250 * pi / 0.5 * pi, resulting in 24500 discs.

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