Conditional Formatting based on sum of pairs of cells.

Hey, having some trouble with some conditional formatting.

I have created a table that has working hours of staff members over many weeks. Week number as column headings (1 to 52) and staff name as Row headings. E.g a row may be

John Smith, 37, 37, 37, 37, 64 (commas to show seperate cells)

How would I go about using conditional formatting so that the formatting changes according to the sum of the values in each pair of cells?
I need to add the total hours of every two weeks for some staff and change the fill colour of both cells accordingly to highlight which weeks staff have worked too many/few hours.

So (B1+C1) would be a pair, the total would decide which fill colour is used on both B1 and C1, and then (D1+E1) would be the next pair and so on.

I have tried using 'a formula to determine which cells to format' and placing =(B1 + C1) = 74 and making it fill the cells green but this appears to be doing (B1+C1) as the first pair and then (C1+D1) as the second and changing the format for the first cell only.

I hope I have describe by problem well enough and that someone will be able to help me out.

If any further clarification is needed just ask and I'll try to explain it more.

Is that formula to be applied to the entire table?

I am looking for the formula just for a single row in the table as different rows(Staff) have different formatting due to people working different shifts.
I'm looking to apply seperate conditional formatting rules to each row individually within the same table.

Thanks for the help!

I'll try and explain more specifically what I need as I can't seem to get either of the formulas above to work.

First number starts at B2 and there is a number in each cell in the row from B2 to Z2

The conditional format needs to work so that B2 & C2 change format as a pair based on the sum of the values within those cells, then D2 & E2 change format as a pair based on the sum of the values within D2 & E2 and continuing all the way till Y2 & Z2.

My apologies, I have it working now, made several little errors that made it appear to not be working.

Thank you very much for your help!