The third level has 80 books because 64 / .8 = <<64/.8=80>>80

The second level has 100 books because 80 / .8 = <<80/.8=100>>100

The first level has 125 books because 100 / .8 = <<100/.8=125>>125

In total there are 369 books because 64 + 80 + 100 + 125 = <<64+80+100+125=369>>369

# Answer

369
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Alex is stacking his books in a pyramid. Each level of the pyramid has 80% as many books as the number of books in the previous level. If he makes four levels and the top level has 64 books, how many books are in the pyramid in total?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
369
Alex is stacking his books in a pyramid. Each level of the pyramid has 80% as many books as the number of books in the previous level. If he makes four levels and the top level has 64 books, how many books are in the pyramid in total?
train