Question

Suppose y varies jointly as x and z. What is y when x = 2 and z = 3, if y = 20 when x = 4 and z = 3?

Answer 1

Answer:

y = 10

Step-by-step explanation:

Given y varies jointly 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 = 20 when x = 4 and z = 3 , then

20 = k × 4 × 3 = 12k ( divide both sides by 12 )

$\frac{20}{12}$ = k , that is

k = $\frac{5}{3}$

y = $\frac{5}{3}$ xz ← equation of variation

When x = 2 and z = 3 , then

y = $\frac{5}{3}$ × 2 × 3 = 5 ×  2 = 10