Mary purchased a package of 13 different plants, but she only needed 9 plants for planting. In how many ways can she select the 9 plants from the package to be planted?

Answer 1

This would be an example of the C(n,r) that I explained in a few posts below.

You are choosing 9 from the 13, and the order really does not matter, so
C(13,9) = 13!/(9!4!) = 715

look for a key labeled _nC_r on your calculator

press
13
2ndF
_nC_r
9
=

you should get 715

Answer 2

yea i was having a problem because the calculator i have doesnt have the F button, but thanks for helping me...it was very confusing to me...