How do you calculate trip fuel based on hourly fuel burn rates?
This would typically be solved iteratively. You start with your mass equal to ZFW and calculate how much fuel you need based on the table:

$$ \mathrm{Fuel}_1 = \mathrm{Fuel}(m=\mathrm{ZFW}) $$

Then you add this fuel to your total weight and repeat the calculation:

$$ \mathrm{Fuel}_2 = \mathrm{Fuel}(m=(\mathrm{ZFW} + \mathrm{Fuel}_1)) $$

which will give you slightly larger result. You repeat this process until convergence, meaning

$$ \mathrm{Fuel}_{i + 1} \approx \mathrm{Fuel}_i $$

and this is your final result.