Question

A BARREL OF THE FOUNTAIN PEN CYLINDRICAL IN SHAPE IS 7 CM LONG AND 5MM IN DIAMETER. A FULL BARREL CAN WRITE UPTO 3300 WORDS ON AN AVERAGE. HOW MANY WORDS CAN BE WRITTEN IN BOTTLE OF INK CONTAINING ONE FIFTH OF A LITRE

Answer 1

Answer:

470000 words. hope this helps. answer in the pic

Answer 2

GIVEN:

• Length of the barrel of a fountain pen = 7cm

• Diameter = 5mm which is $\dfrac{5}{10}cm=\dfrac{1}{2}cm$

TO FIND:

Words that can be written in a bottle of ink containing one-fifth of a litre

FORMULA USED:

Volume of the barrel = $πr²$ [Since its shape is cylindrical]

SOLUTION:

Radius of the barrel = $\dfrac{1}{2×2}=0.25cm$

Volume of the barrel = $πr²h$

$~~~~~~~~~~~~~~~~~~~\implies\dfrac{22}{7}×(0.25)²×7$

$~~~~~~~~~~~~~~~~~~~\implies$ $22×0.0625=1.375cm³$

Also, given volume of ink in the bottle $=\dfrac{1}{5}of~litre=\dfrac{1}{5}×1000cm³=200cm³$

Now, 1.375cm³ ink is used for writing number of words = 3300

$\therefore$ 1cm³ ink is used for writing numbers of words = $\dfrac{3300}{1.375}$

$\therefore$ 200cm³ ink is used for working number of words = $\dfrac{3300}{1.375}×200=480000$

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