Sharp EL-W535TG Operation Manual page 25

Permutations, Combinations
<Example 2>
(1)
(2)
3
(1) When three cards are selected from five cards numbered
1 to 5 and placed in a row, how many possible orderings of
the cards are there?
P
5 3
(2) When three cards are selected from five cards numbered
1 to 5, how many ways of selecting the cards are possible?
Let the number of ways of selecting the cards be C.
There are 3! possible orderings of the cards, and thus
when ordered in a row
C x 3! =
Therefore C is
C =
*This is written as
Operation
5
3
5 3
5 3
= 5 x 4 x 3
P
5 3
P ÷ 3!
5 3
C .
5 3
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