Which of the following numbers are non-prime? A. 11 B. 13 C. 19 D. 21 E. 15…
2020
Which of the following numbers are non-prime?
A. 11
B. 13
C. 19
D. 21
E. 15
Choose the correct answer from the options given below:
- A.
A and E only
- B.
B and C only
- C.
C and E only
- D.
D and E only
Attempted by 321 students.
Show answer & explanation
Correct answer: D
1. Understand the rule: A non-prime (composite) number has divisors other than 1 and itself. 2. Check the given numbers: 11, 13, and 19 are prime numbers because they are only divisible by 1 and themselves. 3. Check the remaining numbers: 21 is divisible by 3 and 7 (3 × 7 = 21). 15 is divisible by 3 and 5 (3 × 5 = 15). Therefore, D and E are non-prime. Final Answer: Option D