Answer: Each small chandelier weighs 7 kg and each large one weighs 28 kg
Explanation:
Let's make x small and y large, for box 1 4x+y=56 and for box 2 4x+5y=168,
4x+5y=168
4x+y=56
subtract 4x
y=56-4x
substitute y into other equation
4x+5(56-4x)=168
distrubute
4x+280-20x=168
subtract 280 and simplify
-16x=-112
divide by -16 (remember, a negative over another negative is a positive)
x=7
substitute x into either equation
4(7)+y=56
28+y=56
y=28
x (small) = 7
y (large) = 28