Answer:
z = 7.5
Step-by-step explanation:
Given that z is directly proportional to x and inversely proportional to y then the equation relating them is
z = [tex]\frac{kx}{y}[/tex] ← k is the constant of proportionality
To find k use the condition when x = 16, y = 5, z = 16, then
k = [tex]\frac{zy}{x}[/tex] = [tex]\frac{16(5)}{16}[/tex] = 5
z = [tex]\frac{5x}{y}[/tex] ← equation of proportionality
When x = 21, y = 14, then
z = [tex]\frac{5(21)}{14}[/tex] = 7.5
