This is a problem of permutation or arrangements, the word PRECALCULUS has 11 letters, of which 3 letters appear twice, we want to get the number of indistinguishable arrangements, this is how we do it,
For our problem, what we do is
The mode would be 1. Mode means the number that is shown the most
Answer:
(a)
>install.packages("air4")
>library(air4)
>attach(UN11)
>plot(ppgdp, fertility)
Check attachments for the plots