The reason you're having a problem is because the cell formats for date and time operate on a system time value. When zero this equates to midnight or 1st of January 1900. Each increment of 1 adds a day, i.e. 24 hours.
The value you are using being hours, is being counted as days, i.e. 24 times too much, so divide by 24.
A1=134
A2=9.58
A3=A1/A2/24
Format cell A3 to HH:MM:SS gives 13:59:15
Hope that helps.