Question

Check whether or not the following are composite numbers:

$39,47,57,69,83,93,103$

Answer 1

Check whether the following numbers are composite or not:

Numbers having more than two distinct factors are known as Composite Numbers.

• $39$ is a composite number. Factors of $39$ are

$$\begin{gathered} 39=1\times 39 \\ 39=3\times 13 \end{gathered}$$

$1,3,13,39$ are the factors of $39$. Here, factors are more than two distinct factors. So,$39$ is a composite number.

• $47$ is a prime number. Factors of $47$ are

$47=1\times 47$

$1,47$ are factors of $47$. Here, there are only two factors. So, it is not a composite number.

• $57$ is a composite number. Factors of $57$ are

$$\begin{gathered} 57=1\times 57 \\ 57=3\times 19 \end{gathered}$$

$1,3,19,57$ are the factors of $57$. Here, factors are more than two distinct factors. So,$57$ is a composite number.

• $69$ is a composite number. Factors of $69$ are

$$\begin{gathered} 69=1\times 69 \\ 69=3\times 23 \end{gathered}$$

$1,3,23,69$ are the factors of $69$. Here, factors are more than two distinct factors. So,$69$ is a composite number.

• $83$ is a prime number. Factors of $83$ are

$83=1\times 83$

$1,83$ are factors of $83$. Here, there are only two factors. So, it is not a composite number.

• $93$ is a composite number. Factors of $93$ are

$$\begin{gathered} 93=1\times 93 \\ 93=3\times 31 \end{gathered}$$

$1,3,31,93$ are the factors of $93$. Here, factors are more than two distinct factors. So,$93$ is a composite number.

• $103$ is a prime number. Factors of $103$ are

$103=1\times 103$

$1,103$ are factors of $103$. Here, there are only two factors. So, it is not a composite number.

Hence, $39$, $57$, $69$ and $93$ are composite numbers.