Question

What is the composite number between $20$ and $40$?

Answer 1

Composite number between $20$ and $40$.

Composite numbers are the numbers with more than two factors

Now, numbers between $20$ and $40$ those have factors other than $1$ and the number itself are:

$$\begin{gathered} 21=1,3,7,21 \\ 22=1,2,11,22 \\ 24=1,2,3,4,6,8,12,24 \\ 25=1,5,25 \\ 26=1,2,13,26 \\ 27=1,3,9,27 \\ 28=1,2,4,7,14,28 \\ 30=1,2,3,5,6,15,30 \\ 32=1,2,4,8,16,32 \\ 33=1,3,11,33 \\ 34=1,2,17,34 \\ 35=1,5,7,35 \\ 36=1,2,3,4,6,9,12,18,36 \\ 38=1,2,19,38 \\ 39=1,3,13,39 \end{gathered}$$

Since each number has more than two factors,

Thus, composite numbers between $20$ and $40$ are $21,22,24,25,26,27,28,30,32,33,34,35,36,38,39.$