Question

How many four digit numbers can be formed using 7,5,0,2 only once in a number? Explain

Answer 1

7502
2057
5027
2507
5207
7052
7520
7250
5270
5720
2570
2750
5072
5702
2705
7205
2075
2705

Answer 2

Total possible number that can be formed are 24

1) Given digits are:- 7,0,5,2

2) A digit can be used only once.

3) To form a n-digit number, possible numbers would be n!.

4) Hence, the answer would be 4! = 24.

5) For the first digit, we can use any of four digits.

6) Since one of four digit is used, we have only 3 choices for second digits and subsequently 2 choices for third digit and 1 choice for the last digit.

7) So, the possible combinations would be 4*3*2*1 = 4!