CHAPTER 5
Permutations and Combinations
15
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=
nPr
nCr
5
SHIFT
4
3
5
nCr
4
0
SHIFT
MODE
3
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A Mathematics Society committee consists of a president, a vice-
president, a secretary and a treasurer. How many ways can such a
committee be chosen from 45 members?
OPERATION
1
. To determine
This means that there are 3,575,880 ways to form the committee.
A group of five students is to be chosen from a class of 30 for a debate.
In how many ways can such a group be formed?
OPERATION
1
. To form a combination of any five students from 30 students, press
This means that the number of combination is 142,506.
Pressing
will erase all memory and return the calculator
to its default mode:
COMP
mode.
45P4
3,575,880
30
Ç
5
142,506
Example 2
Example 1