Aptitude - Numbers - Discussion

Thank you @Nidhin. Now I understand it easily.

@Nidhin.

Thank you for this shortcut. It's really helpful.

Will you tell me the shortcut to remember prime number above 100?

2,5,8- 39 means 23, 29, 53,59,83,89
3-17
6-17
9-7 more easy to memorizing.

This is the easiest way to check prime number.

Ex that 31, So put the nearest square of this number 25<31>36, so square of 31 is something 5. Something, then find the number below 5 prime number i.e. 2 and 3, now check 31 is divisible by this number or not if this is divisible then it is not the prime number, if this is not divisible then it is a prime number.

Identify Prime Number.

11 * 1 = 11.
ODD .N
12=2*6, 3*4, 6*2, 12*1 etc.

2,3,5,7,11 etc .... prime no.

So
31 is not divided by 2,3,5,7,11.etc - so it is prime no.
61 is not divided by 2,3,5,7,11 -so it is prime no.
71 is not divided by 2,3,5,,7,11 so it is prime no.
91 is divided by 7 it is not prime no.
So answer is D-91.

We can use the elimination method here.

The question says we need a number that is completely divisible by (2^32 + 1). So, a number that satisfies this condition will be larger than the given number.

Option A and B are obviously smaller.

Option C and D are the choices.

On a closer analysis we find that even option c is smaller than the actual number.

So we are left with option D as our final answer. You need to use your wit rather than calculation to solve a problem.

13*7=91 so not prime number.

how to solve this question? Please tell me.

The Prime number means any number is divisible by one and itself.