The first thing we must do for this case is to define variables.
We have then:
x: weight of the big box
y: weight of the small box.
We now write the system of equations that models the problem:

We apply the graphic solution.
For this, the solution will be the cut point of both lines.
We have then that the solution occurs for the point:
Note: see attached image
Answer:
Weight of each large box: 15.5 Kilograms
Weight of each small box: 13.25 Kilograms
11 1/3 is the answer in fraction form but i decimal form it is 11.3 and the exact form is 34/3
You have to divide 1575 by 35 which equals 45 and then multiply that by 2 which equals 90. There are 90 foreign students