Is 15 is a composite number or not ?
- As we already know that, the number having factors 1 and the number itself is the prime number.
- And numbers having more than these two factors are the composite numbers.
- To check whether the number 15 is composite or not first we have to find its factors.
Contents
Factors of 15:
- If we have taken numbers from 1, 2, 3…for checking factors of 15, we found that 15 has factors 1, 3, 5 and 15. Hence, we must say that 15 is a composite number.
- Thus, 15 is the composite number.
- If we multiply 15 by 1, 2, 3, then we get the multiples of 15 which are 15, 30, 45…and so on.
About the number 15:
- 15 has more than two factors which are 1, 3, 5 and 15 and hence it is the composite number.
- 15 is the odd composite number and it is not the perfect square also.
- If we divide 15 by 1, 3, 5 and 15 then we get remainder as zero. Hence, 1, 3, 5 and 15 are the factors of 15.
Note:
- 15 is not the perfect square.
- Factors of 15: 1, 3, 5, 15
- Prime factors of 15: 3 and 5
Conclusion:
- 15 is the composite number which has factors 1, 3, 5 and 15.
- And hence, 15 is not the prime number.
Multiple Choice Questions:
1) 15 is a
a) odd number
b) Prime number
c) Composite number
d) Both a and c
Ans: d) both a and c
2) The prime factors of a composite number 15 are
a) 1
b) 3 and 5
c) Both a and b
d) 151
Ans: b)3and 5
3) 1 is the not prime factor of 15 because
a) It is the prime number
b) 1 is neither prime nor composite number
c) Both a and b
d) Given statement is false
Ans: b) 1 is neither prime nor composite number