If the issue ticket was raised on some business day the SLA to close that ticket is 5 days excluding the date when it was raised. Please note that here we need to ignore the weekends and holidays.
i,e If the ticket was raised on 20-Feb-2019 then SLA to close that particular ticket is 27-Feb-2019. Let say if 22-Feb-2019 is a holiday then in that case SLA to close the ticket should be 28-Feb-2019. How can we achieve this.