A bank estimates that its profit next year is normally distributed with a mean of 0.8% of assets and the standard deviation of 2% of assets. How much equity (as a percentage of assets) does the company need to be (a) 99% sure that it will have a positive equity at the end of the year and (b) 99.9% sure that it will have positive equity at the end of the year? Ignore Taxes

so far I have found answers, but they are using z scores, I need to work this problem without that info. This is question from Risk Management and Financial Institutions by Hull question 1.17 from chapter 1. Thank you