Below is an instruction that describes a task. Write a response that appropriately completes the request in English. Please answer in English.

### Instruction:
Anna is reading a 31-chapter textbook, but she skips all the chapters that are divisible by 3. If it takes her 20 minutes to read each chapter, how many hours does she spend reading total?

### Response:
First divide 32 by 3, ignoring the remainder, to get 32 / 3 = 10.33..., which means 10 chapters are divisible by 3.
Then subtract those chapters from the total number of chapters to get 31 chapters - 10 chapters = <<31-10=21>>21 chapters.
Then multiply the number chapters by the time to read each chapter to find the total time she spends reading: 20 minutes/chapter * 21 chapters = <<20*21=420>>420 minutes
Then divide that number by the number of minutes per movie to find the total time spent reading in hours: 420 minutes / 60 minutes/hour = <<420/60=7>>7 hours
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