The kitchen of an apartment is 20 feet long and 30 feet wide. When the apartment is renovated, the length is decreased by 10% and the width is increased by 5%. By what percent does the area of the room change?
The original area of the kitchen is 20 feet * 30 feet = <<20*30=600>>600 square feet.
The new length of the kitchen is 20 feet - 20 feet * 0.10 = <<20-20*0.10=18>>18 feet.
The new width of the kitchen is 30 feet + 30 feet * 0.05 = <<30+30*0.05=31.5>>31.5 feet.
The new area of the kitchen is 18 feet * 31.5 feet = <<18*31.5=567>>567 square feet.
The percentage change in area is (567 square feet - 600 square feet) / 600 square feet * 100 = -33 / 6 * 100 = -5.5%.
Therefore, the area of the room changes by 5.5%. Answer: \boxed{5.5}.