A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
You may enter the value in cell A1 as 115, in B1 use the formula without quotes "=TEXT(A1/(24*60),"hh:mm")"
Refer the link below for more information:
http://office.microsoft.com/en-us/excel-help/convert-times-HP003056110.aspx