How many numbers between 10 and 10000 can be formed by using the digits $1,2,3,4,5$, if no digit is repeated…
How many numbers between 10 and 10000 can be formed by using the digits $1,2,3,4,5$, if no digit is repeated in any number?
200
775
60
120
Solution
Number of ways of forming two digit number
$
=5 \times 4=20
$
Number of ways of forming three digit number
$
=5 \times 4 \times 3=60
$
Number of ways of forming four digit number
$
=5 \times 4 \times 3 \times 2=120
$
Hençe, the required number of ways
$
=20+60+120=200
$