Answer:
45kg.
Explanation:
Let X be the # of kilograms allowed without a charge.
Let Y be the # of kilograms of luggage carried by person A.
Let Z be the # of kilograms of luggage carried by person B.
Let P be the price / kilogram of excess baggage.
We need to solve for X.
We know the following is true:
Y + Z = 135
(Y - X)*P = 1.35
(Z - X)*P = 2.70
(135 - X)*P = 8.10
Now, it's just the messy problem of solving 4 equations for 4 unknowns. The answer turns out to be:
P = 0.09
Z = 75
Y = 60
X = 45
Therefore, at most, each person is allowed 45 kilograms of luggage at no additional charge.