Jenna sets a goal of reading 600 pages a month for the month of September (which has 30 days). She knows that she'll be really busy at work the four weekdays starting on the 13th, so she won't have time to read. She can also read 100 pages on the 23rd, when she'll have a long boring flight. If she reads the same number of pages every other day, how many pages a day does she need to read?
First, subtract the number of days Jenna can't read from the number of days in September: 30 days - 4 days = <<30-4=26>>26 days.
Then subtract the one day when Jenna will read 100 pages: 26 days - 1 day = <<26-1=25>>25 days.
Now subtract the 100 pages Jenna will read on her flight from her overall goal: 600 pages - 100 pages = <<600-100=500>>500 pages.
Finally, divide that number of pages by the number of days Jenna will read the standard amount: 500 pages / 25 days = <<500/25=20>>20 pages per day.
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