A merchant mixed \( 10 \) lb of a cinnamon tea with \( 6 lb \) of spice tea. The \( 16 \) -pound mixture cost \( \$ 43 \) . A second mixture included \( 12 lb \) of the cinnamon tea and \( 10 lb \) of the spice tea. The 22-pound mixture cost \( \$ 60 \) . Find the cost per pound of the cinnamon tea and of the spice tea.
A linear function that models data is described below. Find the slope of the model. Then describe what this means in terms of the rate of change of the dependent variable per unit change in the independent variable. The linear function \( f ( x ) = - 0.41 x + 28.6 \) models the percentage of adults in a country who smoked cigarettes, \( f ( x ) \) , \( x \) years after \( 1997 \) .
The slope is \( \square \) . (Type an integer or a decimal.)