My question.

These questions are pulled from the Mickelson book.The solutions can be found on pages 198 and 199.

Page: 179

Number:16)

Letter: c)

Evaluate(worth one mark):

10! 4! / 8! 6!

= (1*2*3*4*5*6*7*8*9*10)(1*2*3*4) /

(1*2*3*4*5*6*7*8) (1*2*3*4*5*6)

= 9 * 10 /

5 * 6

90 / 30

= 3

Second question (page 180, number 23) (worth two marks):

How many different groups of four letters can be made from the letters A, B, C, D, E, and F if the letters can only be used once?

P(6, 4) = 6! / (6 - 4)! = 6! / 2! =

1 * 2 * 3 * 4 * 5 * 6 /

1 * 2

= 3 * 4* 5 * 6

= 360

We can create 360 groups of four letters from A, B, C, D, E, and F if the letters can only be used once.