The term "net" means "after considering everything." So this is asking you to compare the price after the 30% increase and 20% decrease to the original price. Not sure what choices you were given, but it seems to me the answer is wrong. If the original price was $100 then after a 30% increase the new price was $130. Then when a 20% reduction is applied to the $130 figure the new "net" price is 80% of $130 = $104. So the net change in price is +4%.