Question

Which of the following is not a composite number?
A). 352 + 6
B). 357 + 7
C). 352 + 7
D). 353 + 1

Answer 1

Hint: To have a better approach in these types of questions you should be aware about the concepts of composite numbers in this question. Add the given numbers in the option and find the factors of the numbers to find the answer to the question.

Complete step-by-step solution -
Let’s add the numbers in the options to find the factors of the numbers
For the first option 352 + 6 = 358 let’s find the factors of 358
To find the factors of 358 let’s use the method of factorization

2	358
179	179
	1

Since 358 is an even number it have factors more than 1 and itself therefore 358 is a composite number
In the $2^{nd}$ option we have 357 + 7 = 364 let’s find the factors of 364
By factorization method

2	364
2	182
91	91
	1

Since 364 is an even number it have factors more than 1 and itself therefore 364 is a composite number
For $3^{rd}$ option we have number 352 + 7 = 359
Using the method of factorization to find the factors of 359

359	359
	1

Since 359 is an odd number it have doesn’t have factors more than 1 and itself therefore 359 is not a composite number
For $4^{th}$ option we have number 353 + 1 = 354
Let’s use the method of factorization to find the factors of 354

2	354
177	177
	1

Since 354 is an even number it have factors more than 1 and itself therefore 354 is a composite number
Since the numbers 352 + 6, 357 + 7 and 353 + 1 are the composite number where as the number 352 + 7 is not a composite number
Hence option C is the correct option.

Note: The concept of composite number which we used in the above solution can be explained as the number which is the multiple of 2 or more than 2 integers such that it has at least 1 divisor excluding number 1 and the number itself. These numbers which are the divisor of the number are named as the factors of number example of composite number are even numbers accept 2 and non-prime numbers.