Let
be the number of hours worked at Job A and
the number of hours at Job B. Then

and

From the first equation,

and substituting this into the second gives



Answer: 24 days
Step-by-step explanation:
Takes her 4 days to read 1/2 of a 200 page book, or 100 pages.
4 days = 100 pages
X days = 600 pages
24 days = 600 pages