I receive a spreadsheet with data that I need to copy and paste this in to
another spreadsheet.

The data appears as follows in the following format:
1378:20:00
675:00:00
11:40:00
1:40:00
0:00

I need to write a formula or convert this into the following format:
1378.20
675.00
11.40
1.40
0.00

How can this be accomplished?