Question

A girl can finish a book in $25$ days if she reads $18$ pages of every day. How many days will she take to finish, if she she reads $15$ pages every day?

Answer 1

From the question,
Number of days taken to finish the book if she reads $18$ pages every day $=25$
Number of days taken to finish the book if she read $1$ page every day $=(18\times 25)$
$\therefore$ Number of days taken to finish the book if she reads $15$ pages every day $=(18\times 25)/15$
$=30$ days