中等MATH-NUMB-009
A price decreases by 20% and then increases by 20%. What is the overall change?
A. No overall change
B. A decrease of 4%✓ 答案
C. An increase of 4%
D. A decrease of 2%
解說
The multipliers are 0.8 and then 1.2. Their product is 0.96, so the price finishes 4% lower. Equal percentage changes in opposite directions do not cancel.