Given:
a set of plants can be installed in 6 hours by 12 workers
landscaper want a set of plants to be installed in 4 hours.
Variables are inversely related. This means that holding other things constante when one variable increases, the other variable decreases. The two variables are number of hours and number of workers. For the number of hours to decrease, we must increase the number of workers.
y = k / x
number of hours = constant rate / number of workers
standard: 6 hours , 12 workers
6 = k / 12
6 * 12 = k
72 = k
desired result: 4 hours
4 hours = 72 / x
4x = 72
x = 72/4
x = 18
We need 18 workers to finish a set of plants in 4 hours.