While I was up to this question I got stuck. You have multiplied the power of 160 and 32 at the second last step to get 5120 but i think in question it is given power to power again. like power to 2 is 160 and again power to 160 is 32 which seems to be lot more bigger but not 5120. I hope you got me. I have also attached the screenshot of the question.
You are right