This question is Based on Mensuration Chapter of M.L Aggarwal book for ICSE BOARD for class 10.
Here a barrel of a fountain pen is given of cylindrical in shape with given height and diameter.
How many words would use up a bottle of ink containing one-fifth of a litre?
This is the Question Number 11, Exercise 17.1 of M.L Aggarwal.
Deepak BoraNewbie
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 will be used up when writing 310 words on an average. How many words would use up a bottle of ink containing one-fifth of a litre?
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Height of the barrel of a pen, h = 7 cm
Diameter, d = 5mm = 0.5 cm
Radius, r = d/2 = 0.5/2 = 0.25 cm
Volume of the barrel of pen, V = r2h
= (22/7)×0.252×7
= 1.375 cm3
Ink in the bottle, = one fifth of a litre
= (1/5)×1000 = 200 ml
Number of words written using full barrel of ink = 310
Number of words written by using this ink = (200/1.375)×310 = 45090.90 words
Round off to nearest hundred, we get 45100 words.
Hence the number of words written using the ink is 45100 words.