Question

Show all work. Mary purchased a package of 18 different plants, but she only needed 15 plants for planting. In how many ways can she select the 15 plants from the package to be planted?

Answer 1

\[Ways = C^{18}_{15} = 18C_{15}\]

\[\huge \color{green}{^nC_r = \frac{n!}{(n-r)! \times r!}}\]