Question

what is the number of 3 digit of formed by using digit 3,5,9 taking each digit exactly ones in dash

Answer 1

Step-by-step explanation:

24

Let's take box with 3 columns( since its a 3 digit number)

For the number to be even, it's last digit has to be a even number I.e. 4,6 Can be used. using 4, write the digit 4 in the units place of the number I.e. In the box. Apart from the digit 4 we have four more numbers which can be filled in the hundreds place in 4 ways and tens place in 3 ways ( 3 Cz one of the four digit is used)

Number of ways =4*3=12

Similarly for 6. Total number of ways −12+12=24.