Let the weight of a large box be x .
Let the weight of a small box be y .
According to the first condition,
According to the second condition,
Multiplying equation ( 1 ) by 3 ,
Subtracting equation (2) from (3),
Substituting the value of x = 15.75 in equation ( 1 ),
Further,
Thus the weight of a larger box is 15.75 kilograms and weight of a smalller box is 13.75 kilograms.