Answer:
Equation:

when n = 4
Explanation:
Given
Direct Variation: P ∝ n
When n = 15, P = 150
Required
Determine the equation
Her earnings if she sold 4 necklaces
P ∝ n
Convert variation to equation

When P = 150, n = 15 (Substitute these values in the given equation)

Divide both sides by 15


Substitute k = 10 in


------- Equation that relates P and n
When she sold 4 necklaces, n = 4
Substitute n = 4 in the formula above

