Mary read a 105-page book in 5 days. If she continues reading at that rate, how long will it take her to read a 504-page book? (6.RP.3.d, 6.RP.3.b)(1 point)

To determine how long it will take Mary to read a 504-page book based on her reading rate, we first need to find out how many pages she reads per day.

Mary read a 105-page book in 5 days.

To find her reading rate, we calculate:

\[
\text{Pages per day} = \frac{\text{Total pages}}{\text{Total days}} = \frac{105 \text{ pages}}{5 \text{ days}} = 21 \text{ pages per day}
\]

Now, we know that she reads 21 pages per day. Next, we need to find out how many days it will take her to read a 504-page book.

We calculate the number of days required to read 504 pages at her reading rate:

\[
\text{Days required} = \frac{\text{Total pages}}{\text{Pages per day}} = \frac{504 \text{ pages}}{21 \text{ pages per day}} = 24 \text{ days}
\]

So, it will take Mary **24 days** to read the 504-page book.

The correct response is:

**24 days**