Answer:
Small box weighs 13.75 kg & large box weighs 15.75 kg
Explanation:
We can write 2 simultaneous equation and solve for weight of each box.
Let weight of large box be l and small box be s.
"3 large boxes and 5 small boxes has a total weight of 116 kilograms":

and
"9 large boxes and 7 small boxes has a total weight of 238 kilograms":

Now we can solve for l in the 1st equation and put it into 2nd equation and get s:

now,

now we plug in 13.75 into s into equation of l to find s:
