I require help on the below question on normal distribution.

**"An e-commerce company tries to settle the customer complaints on refund within 5 days. If a refund is not processed within 5 days, then the company has to provide coupons for Rs.500 to the customer. If the company targets that at least 90% of the refund related complaints should be processed within 5 days, then what should be mean processing time. The standard deviation is 2 days."**I'm confused whether the given 90% is P value as 0.9 or to be taken as alpha 0.1. Please help with the solution.

Thanks in advance.