Answer:
60%
Step-by-step explanation:
40 ft² is 100%
so, 1% = 0.40 ft²
now we need to ask, how often did 1% fit into the 16 ft².
that means
16 / 0.4 = 16 / (4/10) = (16×10)/4 = 160/4 = 40 %
so, the new, smaller area is only 40% of the original area.
and that means, that the area decreased by 100-40 = 60%
