Set this up as a system of equations. The first will be the 2 large boxes plus the 3 small boxes weigh 83 kg, the second will be the 4 large boxes plus the 8 small weigh 197 kg. 2L + 3s = 83 and 4L + 8s = 197. Solve one of them for either variable. Let's solve the second one for L: L = -2s + 49.25. Sub that value of L into the first equation: 2(-2s + 49.25) + 3s = 83. Distribute through the parenthesis to get -4s + 98.5 + 3s = 83. Combine like terms to get -s =-15.5. or s = 15.5. So a small box weights 15.5 kg. A large box is -2(15.5) + 49.5, which is 18.5 kg.