If x and y are positive numbers and z = xy^2, a 60 percent increase in x and a 30 percent decrease in y would result in which of the following changes in z?	Choose one.
A) decrease of 12.5%
B) decrease of 21.6%
C) increase of 4.8%
D) increase of 12.5%
E) increase of 24.3%
After the changes, z = 1.6x*(0.7y)^2 = (1.6*0.49)xy^2 = 0.784*z   The answer is decrease of 21.6%.
<result>B</result>
If x and y are positive numbers and z = xy^2, a 60 percent increase in x and a 30 percent decrease in y would result in which of the following changes in z?