Question

The board of directors of a corporation must select a president, a secretary, and a treasurer. In how many possible ways can this be accomplished if there are 21 members on the board of directors?

Answer 1

7980 ways

Explanation:

Pretty simple.

we are finding variation.

Variation = N factorial/ (N-P)factorial/

N = the total number of elements we have available

P = the number of elements out of n we need to select

N = 21

P = 3

Variation = 21 factorial/(21-3)factorial = 21 factorial/ 18 factorial

Variation = 21x20x19x 18factorial/ 18 factorial

Variation = 21x20x19 = 7980 possible ways of selecting 3 positions out of a board of 21 members.

is it clear?

Answer 2

Answer:7980 ways

Explanation:

When select predident:21 ways

When select secretary: 20 ways

When select treasurer: 19 ways

It is permutation

N permutation r=NPR

20permutation3=21×20×19= 7980 ways