If Anna can read 1 page in 1 minute, then her speed is 1/1 = <<1/1=1>>1 page per min

If Carole can read at Anna's same speed then her speed is also 1 page per min

If Carole is only half the speed of Brianna, then that means Brianna is twice as fast as Carole, so 2 * 1 page per min = <<1*2=2>>2 pages per min

If a book is 100 pages long and Brianna can read 2 pages per minute, then it will take her 100/2 = <<100/2=50>>50 minutes to read the book

# Answer

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<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Anna can read 1 page in 1 minute. Carole can read as fast as Anna but at half the speed of Brianna. How long does it take Brianna to read a 100-page book?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
50
Anna can read 1 page in 1 minute. Carole can read as fast as Anna but at half the speed of Brianna. How long does it take Brianna to read a 100-page book?
train