Answer:
15
Step-by-step explanation:
Given that:
y = 15x
y = amount of money made by club members made for washing cars
x = number of cars washed
From the equation given ;
Amount made is directly proportional the number of cars washed
Mathematically,
y α x
y = kx
Where k = constant of proportionality
Comparing the given equation with
y = kx
y = 15x
k = 15 = constant of proportionality
