Half of the book means 500 / 2 = <<500/2=250>>250 pages.

Reading the first half took Jane 250 / 10 = <<250/10=25>>25 days.

Reading the second half of the book took Jane 250 / 5 = <<250/5=50>>50 days.

So in total Jane needed 25 + 50 = <<25+50=75>>75 days to read the whole book.

# Answer

75
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Jane had a 500 page book to read. The first half of the book Jane read with a speed of 10 pages per day, and the second half with a speed of 5 pages a day. How many days did Jane spend reading this book?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
75
Jane had a 500 page book to read. The first half of the book Jane read with a speed of 10 pages per day, and the second half with a speed of 5 pages a day. How many days did Jane spend reading this book?
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