Someone 1). evaluate c(20,18). a) 380 b) 190 2). evaluate c(6, 6). a) undefined b) 1

C(20,18) gives us our n and r

n = 20
r = 18


With factorials

You can equate n! to 20 * 19 * 18! on top

2! on bottom with 18!

Which you can remove 18! because of division giving you

20 * 19 / 2!

This changes to 20 * 19 / 2 = 190

As for C(6,6), these always equate to 1

Num of plants = (original#ofplants)*(1.6)^t