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The barrel of a 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 on writing 3300 words on an average. How many words can be written in a bottle of ink containing one fifth of a litre

Solution:

Given, a barrel in a fountain pen, cylindrical in shape, is 7 cm long and 5 mm in diameter.

A full barrel of ink in the pen is used to write 3300 words on an average.

We have to find the number of words that can be written in a bottle of ink containing one fifth of a litre.

Volume of cylinder = πr²h

Given, height of barrel h = 7 cm

Diameter of barrel = 5 mm

Radius = 2.5 mm

1 cm = 10 mm

So, radius r = 2.5/10 = 0.25 cm

Volume of cylindrical barrel = (22/7)(0.25)²(7)

= 22(0.25)(0.25)

= 1.375 cm³

With 1.375 cm³ of ink, 3300 words can be written.

Volume of ink in bottle = 1/5 litre

= 0.2 litre

= 200 cm³

With 200 cm³ of ink, the number of words that can be written = 3300(200)/1.375

= 660000/1.375

= 480000

Therefore, 480000 words can be written using 1/5 litre of ink in a bottle.

✦ Try This: The barrel of a fountain pen, cylindrical in shape, is 9 cm long and 6 mm in diameter. A full barrel of ink in the pen is used up on writing 5500 words on an average. How many words can be written in a bottle of ink containing one fifth of a litre?

☛ Also Check: NCERT Solutions for Class 10 Maths Chapter 13

NCERT Exemplar Class 10 Maths Exercise 12.4 Problem 4

The barrel of a 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 on writing 3300 words on an average. How many words can be written in a bottle of ink containing one fifth of a litre

Summary:

The barrel of a 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 on writing 3300 words on an average. 480000 words can be written in a bottle of ink containing one fifth of a litre

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