Question

the 4 digit number that can be formed out of 7 digits 1 2 3 5 7 8 9 such that no digit is repeated in any number and greater than 3000 are

Answer 1

First Digit:

Number of choices for the first digit = 5

First digit must be at least 3

The choices are [ 3, 5, 7, 8, 9]

Second Digit:

Number of choices for the second digit = 6

Any number except the one taken by first digit

Third Digit:

Number of choices for the third digit = 5

Any number except the ones taken by first and second digit

Fourth Digit:

Number of choices for the fourth digit = 4

Any number except the ones taken by first, second or third digit

Total combinations:

Total number of possible combinations = 5 x 6 x 5 x 4 = 600

Answer: 600 possible combinations.