General

Grade 12 Data Management help, life at risk

I have some questions I'm unable to figure out, help would be appreciated!

- 14)Consider the word SARCASM:

a) How many different 4-letter combinations exist using the letters in this word? [3]
There are

b) How many different 5-letter permutations exist using the letters in this word? [3]
Note: SARC and SRAC are considered the same combination but different permutations

- 12) Prove that nPr+1 = (n-r)(nPr)

- 5) Solve for the value of n: nP4 = (90)( nP2). You must show all your work. [4]

- 3) How many integers smaller than 40,000,000 can be formed by using all the digits in {1,1,3,4,4,5,5,6}?