Question

The barrel of a fountain pen, cylindrical in shape, is 7 cm long and 5 cm in diameter. A full barrel of ink in the pen will be used up on writing 330 words on an average. How many words would use up a bottle of ink containing on fifth of litre?

Answer 1

ANSWER:
Height of the barrel = h = 7 cm
Radius of the barrel = r = 2.5 mm = 0.25 cm
Volume of the barrel =$\pi r^{2}h$
= $\frac{22}{7}\times 0.25\times 0.25\times 7=22\times 0.25\times 0.25=1.375c{m}^3$
i.e., 1.375$c{m}^3$ of ink is used for writing 330 words
Now, number of words that could be written with one-fifth of a litre, i.e., 15×1000$c{m}^3$ =
330 x 11.375 x15 x 1000=48000
∴ 48000 words would use up a bottle of ink containing one-fifith of a litre.