Answer:
8 grams
Explanation:
The balance is in equilibrium, so the weights of the two sides are equal.
Let the weight of a square be s.
Left side: 2s + 4
Right side: s + 3(4) = s + 12
The weights are equal, so we set the two expressions equal.
2s + 4 = s + 12
s = 8
Answer: The weight of a square is 8 grams.