Question

How many ways can three different numbers be selected from 10 numbers to open a keypad lock?

Answer 1

There are 720 ways through which 3 numbers can be selected from 10 numbers to open a keypad lock.

Given that there are 10 numbers are 3 numbers are required to open a keypad lock.

Permutations are the number of ways in which objects can be selected without replacements to form subsets.

It is expressed as n$P_{r}$=n!/(n-r)!.

Factorial of a number is the product of consecutive numbers less than the number.

Total numbers available=10

Numbers to be selected=3

Number of ways can be found by using permutations.

Number of ways =10$P_{3}$

=10!/(10-3)!

=10!/7!

=10*9*8*7!/7!

=10*9*8

=720 ways.

Hence there are 720 ways through which 3 numbers can be selected from 10 numbers.

Learn more about permutations at brainly.com/question/1216161

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