Kwan reads one page per minute, which means he can read 30 pages in half an hour (since there are 30 minutes in half an hour).
To find out how long it will take him to read a 400-page book at this rate, we can divide the total number of pages by the number of pages he reads each day:
\[ \text{Number of days to finish the book} = \frac{\text{Total pages}}{\text{Pages read per day}} = \frac{400}{30} \]
Calculating this:
\[ \frac{400}{30} \approx 13.3333 \]
Since he can only read for whole days, we take the ceiling of this value, meaning he will take 14 days to finish the book.
Now, we need to determine the day of the week 14 days after Saturday.
Starting from Saturday:
- 1 day later: Sunday
- 2 days later: Monday
- 3 days later: Tuesday
- 4 days later: Wednesday
- 5 days later: Thursday
- 6 days later: Friday
- 7 days later: Saturday
- 8 days later: Sunday
- 9 days later: Monday
- 10 days later: Tuesday
- 11 days later: Wednesday
- 12 days later: Thursday
- 13 days later: Friday
- 14 days later: Saturday
Thus, Kwan will finish the book on a Saturday.