Surface Areas&Volumes

Volume of the barrel of pen = r²H = (22/7) x (2.5)² x (7) = 137.5 cm³

1000 cm³ = 1 litre

1 cm³ = 1/ 1000 litre

137.5 cm³ = (137.5/ 1000) litre.

(137.5/ 1000) litre of ink can be used to write 310 words.

1/5  lite of ink can write = (310 x 1000)/ (137.5 x 5)

                                         = 451 words (approx)