Question

How many positive factors of 40 are there?
A.3
B.4
C.6
D.8

Answer 1

Hint: In this problem, we have to find the positive factors of the number 40. We know that 40 is a composite number, which has more than two factors. Factors of 40 are the number which can divide the original number 40 and result in the whole number as quotient. We can now find the factors of 40 using the multiplication method.

Complete step-by-step solution:
Here we have to find the factors of 40.
We know that factors are pairs of numbers which on multiplication gives the original number.
We know that 40 is a composite number, which has more than two factors.
We can now write the factors of the number 40, whose pair on multiplication gives 40.
\[\Rightarrow 40\times 1=40\]
We can now see that when 1 and 40 is being multiplied, we get the original number 40 itself.
Similarly, if we multiply the following numbers, we will get the required answer,
\[\begin{align}
  & \Rightarrow 20\times 2=40 \\
 & \Rightarrow 10\times 4=40 \\
 & \Rightarrow 8\times 5=40 \\
\end{align}\]
Here, we can see that, we have 8 numbers, which are the factors of 40, they are
\[\Rightarrow 1,2,4,5,8,10,20,40\]
There are 8 positive factors of 40.
Therefore, the answer is option D.8.

Note: We can also find the factors by division method. We should remember that factors are pairs of numbers which on multiplication gives the original number. We should also know the difference between prime and composite as composite numbers have more than two factors, but the prime number is a factor in itself.