We know that 9 artists created 18 classrooms at a constant rate, and we want to know how many classrooms can a team of 15 artists paint. This can be represented as:
Where x represents the value of classrooms painted by 15 artists.
As we know, if we have more artists, they will paint more classrooms. So, the magnitudes are directly proportional. The proportion will become:
Now, we multiply means and extremes, to obtain:
Lastly, we divide by 9 to both sides, and we get:
This means that 15 artists will paint a total of 30 classrooms.