Still having problems with converting h:m to decimal

I've been reading through all threads and trying out the various formulas but I'm still having problems converting. This is what I have per week (the times vary).

Start Finish Break Hours
10:00 19:00 00:30 8:30:00
07:00 19:00 00:30 11:30:00
07:00 19:00 00:30 11:30:00
07:00 19:00 00:30 11:30:00
07:00 17:00 00:30 9:30:00
Total 52:30:00
Basic 35:00:00
OverT 17:30:00

I now need to convert the Basic and OverT to decimal and multiply them by the rate of pay. for instance

Running total
Basic 175.00 x 9.00 = £1575.00
OverT 87.50 x 12.00 = £1050.00
Gross = £2650.00

For some reason 35:00:00 always comes out as 11.00.

I'm probably being a thicko and missing something simple, but I'm an electrician not a computer wizz.

For some reason 35:00:00 always comes out as 11.00.

Format as [h]:mm instead of h:mm