Question

In the given figure, a cylindrical wrapper of flat tablets is shown. The radius of a tablet is 7 mm and its thickness is 5 mm. How many such tablets are wrapped in the wrapper? 

Answer 1

Radius of a tablet, r = 7 mm

Thickness of a tablet, h = 5 mm

Radius of cylindrical wrapper, R = \[\frac{14}{2}\] = 7 mm

Height of wrapper (H) = 10 cm

= 10 × 10 mm

= 100 mm

Let n be the number of tablets wrapped in the wrapper.

\[n = \frac{\text{ Volume of the cylindrical wrapper} }{\text{ Volume of each tablet } }\]

\[ \Rightarrow n = \frac{\pi R^2 H}{\pi r^2 h}\]

\[ \Rightarrow n = \frac{\left( 7 \right)^2 \times 100}{\left( 7 \right)^2 \times 5} = 20\]

Thus, 20 tablets are wrapped in the wrapper.