I like black chicken that lay black eggs

Chance of boy: 627/1,358
Chance of girl: 731/1,358
Hello !
You have to do as follow :

Answer:
(a) 64 days
(b) 2 phones calls
Step-by-step explanation:
Given a number n, the addititive inverse is -n since n+(-n)=0. However
n+(-n) is the same as n-n which is 0 also.
SO adding the additive inverse it the same as subtracting