Final answer:
The area of the new square, after being reduced by a scale factor of 1/5, is 4 square units.
Step-by-step explanation:
The question asks about the area of a new square after the side length has been reduced by a scale factor of 1/5. The original square has sides of 10 units, so when we apply the scale factor, the new side length will be 10 * (1/5) = 2 units. To find the area of the new square, we need to square this new side length: 2 * 2 = 4 square units. Therefore, the area of the new square is 4 square units, which corresponds to option b) 4.