Brain weight b as a function of body weight w in fish has been modeled by the power function b = 0.007w2/3, where b and w are measured in grams. a model for body weight as a function of body length l (measured in centimeters) is w = 0.12l2.53. if, over 10 million years, the average length of a certain species of fish evolved from 16 cm to 24 cm at a constant rate, how fast was this species' brain growing when the average length was 18 cm? (round your answer to four significant figures.)