# Combinations; Random Number And Seed - HP 10bII+ User Manual

Financial calculator.

Example
Using five books labeled A, B, C, D, and E, how many different ways can three books be
placed on a shelf?
Table 12-15 Example calculating permutations
Keys
V]<D4
Æ
or, using
VÆD]<

## Combinations

The nCr function calculates the number of different sets, or combinations, of n items taken r
at a time. No item can occur more than once in the set of r items, and different orders of the
same r items are not counted separately. This is calculated using the formula:
COMBINATIONS
Example
Using five colored balls, how many different color combinations of three colors can be
chosen?
Table 12-16 Example calculating combinations
Keys
V]9D4
Æ
or, using
VÆD]9
.

### Random Number and Seed

The 10bII+ includes a random number generator function that generates a pseudo-random
number in the range 0 < x < 1. To store a seed value, type a positive number and press
\w]6
seed value.
:
n!
=
--------------------- -
n r
(
:
. Storing a value of 0 will select a random number and store it as the
Display
Description
60.00
Calculates permutations of n
items taken r at a time.
60.00
)!r!
Display
Description
10.00
Calculates combinations of n
items taken r at a time.
10.00
Statistical Calculations 127