Answer:
D
Explanation:
Given y varies directly as x and z then the equation relating them is
y = kxz ← k is the constant of variation
To find k use the condition y =
when x = 1 and z = 4 , then
= k × 1 × 4 = 4k ( divide both sides by 4 )
= k
y =
xz ← equation of variation
When x = 6 and z = 3 , then
y =
× 6 × 3 =
× 18 = 2 × 6 = 12