mPn =

m!

(---m------–----n----)--!

where m, n are integers and 69 ≥ m ≥ n ≥ 0.

Use the following HP-12C program to calculate the number of possible permutations.

KEYSTROKES

 

 

DISPLAY

 

 

 

 

 

CLEAR

 

00-

 

 

0

 

01-

44

0

 

 

02-

 

34

 

 

 

 

 

 

 

03-

43

3

 

 

 

 

 

 

 

04-

43

36

 

 

 

 

 

0

 

05-

45

0

 

 

06-

 

30

 

 

 

 

 

 

 

07-

43

3

 

 

 

 

 

 

 

08-

 

10

 

 

 

 

00

 

09-43, 33

00

 

 

 

 

 

 

REGISTERS

 

 

n: Unused

 

i: Unused

 

PV: Unused

 

PMT: Unused

 

FV: Unused

 

R0: n

 

 

R1-R.8: Unused

 

 

 

 

1.Key in the program.

2.Key in m and press .

3.Key in n and press to calculate mPn.

4.For a new case go to step 2.

Example: How many ways can 10 people be seated on a bench if only 4 seats are available?

Keystrokes Display

120