Question

The barrel fountain pen cylindrical in shape is $7$cm long and $5$mm in diameter.A full barrel of ink in the pen is used up in writing $330$ words.On an average how many words would be used up a bottle of ink containing one fifth of a litre?

Answer 1

Given length of cylindrical shaped barrel = 7 cm

Diameter of barrel = 5 mm = $\frac{5}{10}cm$

$\therefore$ Radius of barrel = $\frac{5}{20}=\frac{1}{4}cm$

Volume of cylindrical barrel = $\pi r^{2}h$

$=\frac{22}{7}\times \times (\frac{1}{4}{)}^2\times 7=1.375c{m}^3$

Now, volume of ink in the both = ${\frac{1}{5}}^{th}$ of 1 l

$=\frac{1000}{5}c{m}^2(\because 1l=1000c{m}^3)$

$=200c{m}^3$

Now, one fall barrel can white 330 words

$\Rightarrow 1.375c{m}^3$ of ink white 330 words.

$\therefore 200c{m}^3$ of ink can white = $\frac{330}{1.375}\times 200$ words

= 48000 words