36 hours is the task.
Suppos your x is 6 which ar the workers involved.

So, to complete the task of 36 hours ,6 workers will work 6 hours each

If you had 2 workers, essentially the worker will not be 6 but 8 and the task of 36 hours will be executed in less time and therefore y is < 36

Turns out B is greater

Hey,

No need even for explanation.

It is just the more workers, the less hours. If x worker(s) complete(s) the job within 36 hours, x+2 workers are gonna necessarily be expected to complete the same job on less hours. It is quite linear logic. (Answer, though.)

In reality, and just to your information, that might not how it works, with what is called the diminishing return of the labour. It may proceed in the shape of concave parabol rather than linear line. (peregrination)