Answer:
150 hours
Explanation:
Bill receives $800 as monthly stipend. But after this statement, it says Bill also works at a bookstore. So, it should mean that Bill does not receive $800 from the bookstore. He receives $800 from another job because of the word "also" which is mentioned in the second statement.
If the question is, to find out the number of hours Bill has to work each month if he assumes his monthly income to be $1,200 then 1200/8 = 150
But if the question is trying to mean that Bill receives $800 as a monthly stipend from the bookstore then this answer is wrong.
Then, we would have to calculate the difference.
$1200 - $800 = $420
Time = $420/8 = 50 hours.
Everything depends on the question. The question however needs some explanation, because this question is not written in a clear way.