Well, you have a problem. If CON1 did 5.73 days @ €1800 per day, then you owe CON1 (5.73)*(1800)= €10314. If CON2 did 5.23 days @ €1800 per day, then you owe CON2 (5.23)(1800)= €9414. iF CON3 did 5 days @ €1200 per day then you owe CON3 (5)(1200)= €6000.

Now, those total €25728, considerably higher than the total €13800. If you want to divide that among the three, according to their percentage of the total work then note that 10314/25728= .40 or 40%. Also 9414/25728= .365 or 37%. Finally, 6000/25728= .23 or 23%. Divide the €13800 in those ratios (multiplying it by each of those fractions). But if they were expecting there regular wage, they will NOT be happy!