Total hours from decimals in time format

Hi

I need to run a total for hours entered in time format but seperated by decimals

The cells I need to add are

Q, Y, AG, AO, AW and total in BB

This may not always be the case though, I may need to add 2 more columns to be added before Q

Total needs to be in time format, with either a decimal or a semi colon (not important)

Example attached

thanks

Squidge