Question

Create and solve a linear equation that represents the model, where squares and triangles are shown evenly balanced on a balance beam. Assume the weight of a square is 1 unit and the weight of a triangle is unknown.

Answer 1

Let the weight of triangle be x units. You are given that the weight of square is 1 unit.

1) On the left side of the balanced beam you can see 3 triangles and 5 squares. The weight on left side is 3·x+5·1=3x+5 units.

2) On the right side of the balanced beam you can see 2 triangles and 7 squares. The weight on right side is 2·x+7·1=2x+7 units.

3) If the whole system is balanced, then the weights on left and right sides are equal:

3x+5=2x+7.

Solve this equation:

3x-2x=7-5,

x=2 units.

Answer: option A