A number is increased by 20% and then decreased by 20%. What is the net change in the number?
4% decrease
Take the number as 100 for easy calculation. After a 20% increase it becomes \(100 \times 1.20 = 120\).
The 20% decrease now applies to 120, not to the original 100: \(120 \times 0.80 = 96\).
The final value 96 is less than the original 100, a fall of 4 in 100, i.e. a 4% decrease. (Equivalently, the net factor is \(1.2 \times 0.8 = 0.96\).)
Hence, there is a net 4% decrease.
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