This is an risk identification scenario to calculate the ALE. I'll upvote the answer who can solve it first

MR. ZUBAYER is the project manager of a Core Banking Project. He has identified a risk in the project, which could cause downtime in the web application. MR. ZUBAYER does not want this risk event to happen so, he takes few actions to ensure that the risk event will not appear. These extra steps, however, cost's an additional Tk.10,000. After sometime, research team identified that MR. ZUBAYER was wrong because the Annual Loss Expectancy (ALE) is less. They informed web application will generate Tk. 20000 revenue per hour and if production application goes down backup application will be up within an hour and database restoration will take additional one hour. Also, the research team did some market study and found this type of attack occurs 2 or 3 times in a year that is around 15%. What is the difference between mitigation cost and Annual Loss Expectancy (ALE)