Answer:
7:50
Step-by-step explanation:
The difference between the starting times is, 5:20 - 4:30, 50 minutes.
Since Seth reads 30 pages an hour, he also reads 1 page every 2 minutes or 3 pages every 6 minutes. Also, since Jamaal reads 40 pages an hour, he also reads 4 pages every 6 minutes. We now know that every 6 minutes, Jamaal reads 1 more page than Seth.
Seth started at 4:30, meaning by the time Jamaal starts reading, Seth has already read 25 pages.
To catch up Jamaal needs to read for 25 * 6 minutes, 150 minutes.
If we add 2 and a half hours to 5:20, we get 7:50.