If a rectangle's length is increased by 20% and its width is decreased by 10%, what is the effect on its area?
Correct: A
Let's assume the original length is L and the original width is W. The original area is L * W. If the length is increased by 20%, the new length is 1.2L. If the width is decreased by 10%, the new width is 0.9W. The new area is 1.2L * 0.9W = 1.08LW, which is 1.08 times the original area, meaning an increase of 8%.