Decimal hours & minutes

Hi I export an Excel report from Time Keeper system (Access Control). When working in Time Keeper it shows the total shift worked by employee times as 7.57 (Which indicates to me that he was 3 minutes short of his full 8 hours.)When I export this report to Excel it obviously reflects as a normal 7.57......(as to where the employee looses more than a half hour) I have endless pay queries due to this.....and would appreciate it if you could assist me in a formula that will make these hours reflect in actual fact only 3 minutes lost!!!!;-(THANKS