Python regarding exponentation

Question

Some how I cannot get this, rather simple, code to round right. My answer: 10737418.219999999 ( actual answer: 10737418.24 )

https://code.sololearn.com/cqpxwaK0etbA/?ref=app

Answer 1

https://code.sololearn.com/cGyqhlPQRncv/?ref=app

But you can solve this task easily if you read the hint carefully