Answer:
50%
Step-by-step explanation:
I'll make images to demonstrate it better. If the length of a rectangle is 6 units and the width is 4 units, it looks like the attached screenshot. This means that the current perimeter is 6 + 6 + 4 + 4, which equals 20.
If the sides are reduced by 50%, it means they are cut in half. The new rectangle looks like the other attached screenshot, and the new perimeter is 3 + 3 + 2 + 2, which equals 10.
The last sentence is asking what percent the new perimeter is of the old perimeter. 10 is 50% of 20, so the final answer is 50%.
