How many five-digit prime numbers can be obtained by using all the digits 1, 2, 3, 4 and 5

How many five-digit prime numbers can be obtained by using all the digits 1, 2, 3, 4 and 5 without repetition of digits?

1. Zero
2. One
3. Nine
4. Ten

Answer: A

Explanation

Prime Number: A prime number is a number which can only be completely divided by 1 and itself.

Given digits are 1, 2, 3, 4 and 5 and you have to make five-digit prime numbers.

If the sum of the digits of a number is divisible by 3, then that number is also divisible by 3. Here, sum of the given digits = 1 + 2 + 3 + 4 + 5 = 15 (which is divisible by 3). So, any number formed using these 5 digits will always be divisible by 3.

Hence, no five-digit prime number can be made using these five-digits (without repetition).

• Exam Year: 2020