Doubt regarding a solving method

[user1842]

Hi everyone,
I was solving one of the homework questions.

While solving I applied the rule to find if a number is prime or composite.

So I noted that 16*16 is the Quantity A roughly so in greg’s “is it Prime” prep swift video I assumed any prime factors ‘A’ would have, will be less than 16 giving me the answer as option B. I am not able to understand where my logic is going wrong

[ganesh]

@user1842

So I noted that 16*16 is the Quantity A roughly so in greg’s “is it Prime” prep swift video I assumed any prime factors ‘A’ would have, will be less than 16 giving me the answer as option B. I

That doesn’t have to be true.

6 * 3 = 18
17 * 1 = 17

17 is less than 18, but has bigger prime factors.