so first will be 11/18 of getting the result of a boy then 10/17 of getting a boy out of whats left then 7/16 out of whats left then we multiply together

and get 385/2448 = 0.15727

the reason we multiply together is the fact in which it is happening consecutively similar to a 70% chance of rain today tomorrow and day after, we multiply them all together (.7*.7*.7) to get .343 of a chance it rains everyday. Which is why we multiply in our question since we want everything to happen

If it is independent then we put each name back in the hat so it is 11/18 then 11/18 then 7/18 we multiply and get 0.1452331