Flora has 50*2= <<50*2=100>>100 books

Gary has 50/2= <<50/2=25>>25 books

Together they own 100+25+50= <<100+25+50=175>>175 books

# Answer

175
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Harry has 50 books in his library. His sister Flora has twice as many books and their cousin Gary has half the books Harry has. How many books do the three of them own together?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
175
Harry has 50 books in his library. His sister Flora has twice as many books and their cousin Gary has half the books Harry has. How many books do the three of them own together?
train