Question

eudoras grandfather has decided to move to a desert island. in his new place he will only have room for 2 of his 4 favorite jazz records. The4 records are by Ben Webster , Miles Davis , Cannonball Adderley , and Lester young. How many combinations of 2 records , in any order , can he make?

Answer 1

Let's call them B, M, C, L
We'll have (without reapeating):
B,M
B,C
B,L
M,C
M,L
C,L

Answer 2

There are 6 combinations.

Explanation:

Given : Eudoras grandfather has decided to move to a desert island. In his new place he will only have room for 2 of his 4 favorite jazz records.

The 4 records are by Ben Webster , Miles Davis , Cannonball Adderley , and Lester young.

To find : How many combinations of 2 records , in any order , can he make?

Solution :

Let, Ben Webster be B

Miles Davis be M

Cannonball Adderley be C

Lester young be L

He will only have room for 2 of his 4 favorite jazz records.

The combinations were arranged in
`^4C_2`

`^4C_2=(4!)/(2!(4-2)!)\\^4C_2=(4* 3* 2* 1)/(2* 1* 2* 1)=6`

Now, the arrangement will be (without repeating):

B,M

B,C

B,L

M,C

M,L

C,L

Therefore, There are 6 combinations.