Question

If the cost of printing a book of 380 pages with 20 lines on each page and on an average 11 words in each line is ₹ 19, then the cost of printing a book with 280 pages 22 lines on each page and 10 words in each line is

Answer 1

$\begin{array}{cccc}\text{Pages}& \text{Lines}& \text{Words}& \text{Cost}\\ 380& 20& 11& 19\\ 280& 22& 10& x\end{array}$

The total cost can be taken for the total number of words.
Total number of words = No. of pages × No. of lines × No. of words

Total number of words in the book of 380 pages:
$W_1=380\times 20\times 11$

Total number of words in the book of 280 pages:
$W_2=280\times 22\times 10$

Total number of words is directly proportional to the total cost.

$\frac{W_1}{W_2}=\frac{C_1}{C_2}$

$\Rightarrow \frac{380\times 20\times 11}{280\times 22\times 10}=\frac{19}{x}$

$\Rightarrow \frac{19}{14}=\frac{19}{x}$

$\Rightarrow x=14$

Hence, the cost of printing a book with 280 pages with 22 lines on each page and 10 words in each line is ₹ 14.