What you need to do is to replace the mixed number plus text with a pure number and then format it to show 60 hrs etc.
Excel stores times as fractions of a day in the decimal part of a number (it also uses the integer or whole number part to store days).
60 hours is 2 days plus 12 hours.
12 hours is half a day, or .5
So 60 hours is 2.5 in Excel's date/time system
Go to an unused cell and enter 2.5
Right-click the cell and choose Format cells...
Select the Number Tab
Choose Custom from the bottom of the list
In the Type: box on the right enter [h] "hrs" (replaces General)
Click OK and your cell will now show 60 hrs
Do the same for 35 hrs
Just to show how this works enter =35/24 in an unused cell
Repeat the formating and the cell will show 35 hrs
I used cells D2 and D3 for this test
Enter =SUM(D2:D3) in another cell
and it shows 95 hrs
If it shows 3.9583, just repeat the cell formating
BTW the [h] forces Excel to show hours beyond 24.
using h will show hours up to 23 and the excess will be held as days, but not shown.
When you click on cell D2 notice that the formula bar shows 02/01/1900 12:00:00 PM because Excel has 2.5 days and as its Date system starts with 1 for 01 January 1900, you see half way through 02 January 1900.
Anyway just copy you newly formatted cells to where you want them.