If x is decreased by 10%, then increased by 50%, then decreased by 20%, by what percent has x increased?
Trap answer: result = (–10 + 50 – 20) = 20%
It is a mistake to add and subtract percent increase and decreases
Instead, we must use multipliers
result = (0.9)x(1.5)x(0.8) = 1.08
Answer = 8% increase