You entered the time as formula text. That is very unusual to do it that way. If you could enter the values as serial-time, that would make your life a lot easier. You could then just use the SUM function on the time values. If you don't know how to enter the time values as serial-time, let us know.
If you, for some reason, must enter the time values as formula text, you could use a helper column to convert the values to serial-time and then sum the converted values. This formula will convert the formula-text in cell A1 to serial-time
=A1/60
Format the cells with the conversion formula as time.