Answer: The required time taken by her to read a 400 page book is 13 hours and 20 minutes.
Step-by-step explanation: Given that Lauren took 12 hours to read a 360 page book.
We are to find the time taken by her to read 400 page book at the same rate.
We will be using the UNITARY method to solve the problem.
We have
Time taken by Lauren to read 360 page book = 12 hours.
So, the time taken by Lauren to read 1 page book will be
[tex]\dfrac{12}{360}=\dfrac{1}{30}~\textup{hour}.[/tex]
Therefore, the time taken by Lauren to read a 400 page book is given by
[tex]\dfrac{400}{30}=13\dfrac{1}{3}~\textup{hour}=13~\textup{hour and}~\dfrac{1}{3}\times60~\textup{minutes}=13~\textup{hour}~20~\textup{minutes}.[/tex]
Thus, the required time taken by her to read a 400 page book is 13 hours and 20 minutes.
