The sum of the left side of these two equations is equal to the same of the right side is these two equations
4x+8y + (-4x+2y) = 20 + 30
10y =50 ( x is eliminated)
y=5
Take this into the second equation
-4x +2y = 30
-4x + 2*5 = 30
x=-5
So x=-5
y=5
The is a 50% chance of being a boy or a girl.....previous siblings do not matter. Every child is an independent event. So even if u had 2 siblings that were boys, the result of the next one being a boy is still gonna be 50%...just as the odds of it being a girl, is 50% as well.
