Prime Digits Roll Number Identification
The question asks to find the roll number that consists only of prime digits. A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. The single digits that are prime numbers are 2, 3, 5, and 7.
Digit Analysis of Options
We need to examine the digits of each given roll number:
- Option 1 (239): Contains digits 2, 3, and 9. While 2 and 3 are prime digits, 9 is not a prime number ($9 = 3 \times 3$).
- Option 2 (357): Contains digits 3, 5, and 7. All these digits (3, 5, and 7) are prime numbers.
- Option 3 (468): Contains digits 4, 6, and 8. None of these are prime digits (4 = 2x2, 6 = 2x3, 8 = 2x2x2).
- Option 4 (579): Contains digits 5, 7, and 9. While 5 and 7 are prime digits, 9 is not a prime number.
Conclusion
Based on the analysis, only the roll number 357 is composed entirely of prime digits.
Similar Questions
- Which of these is both an Integer and a Whole number?
- Which of the following is a non-zero number that belongs to every set: Whole, Integer, Rational, and Real?
- What is the smallest number that must be added to 2378 to make it a perfect square?
- Which of the following is a perfect square and an Integer?
- The set of real numbers includes which of the following?
In the following examples, a number is coded as three digits — representing the remainders when the number is divided by 3, 7, and 11, respectively.
Example 1: $53 \rightarrow 53 \div 3 = 17 \text{ R} 2$, $53 \div 7 = 7 \text{ R } 4$, $53 \div 11 = 4 \text{ R } 9 \rightarrow \text{ Code: } 2, 4, 9$
Example 2: $68 \rightarrow 68 \div 3 = 22 \text{ R} 2$, $68 \div 7 = 9 \text{ R } 5$, $68 \div 11 = 6 \text{ R } 2 \rightarrow \text{ Code: } 2, 5, 2$
By following this method, which is the least number which would have the code - 2, 2, 2?- A student was asked to find the sum of first 20 odd numbers. His answer was 400. Correct?
- Which roll number is a perfect cube?
- Which roll number has a digital root equal to 9? Digital root = sum of digits until one digit remains.
Which of the following statement is TRUE for Whole Numbers?
Important Questions from Number System
Consider the following statements :
1. (25)! + 1 is divisible by 26
2. (6)! + 1 is divisible by 7
Which of the above statements is/are correct ?
If the sum S is divided by 8, what is the remainder ?
If the sum S is divided by 60, what is the remainder ?
Find the sum of squares of the greatest value and the smallest value of K in the number so that the number 45082K is divisible by 3.
How many composite numbers are there from 53 to 97 ?
