Question 1125664: Out of 7 children, in how many ways can a family have at least 1 boy?
How many ways can be made?
Found 2 solutions by math_helper, KMST:
Answer by math_helper(2461)   (Show Source):
You can put this solution on YOUR website! The number family configurations (combinations of children) with 7 children is 
All of them except one (the one with all girls) have at least one boy, 128-1 = 127.
—
Ans:  combinations have at least one boy
Answer by KMST(5328)  (Show Source):
You can put this solution on YOUR website! I am making the very reasonable assumption that those 7 children were born at different times
(with no two of them born at exactly the same time).
Each child could be a boy, or not a boy,
giving 2 possibilities per child,
and  different ways to make up a family.
Only  of those  different ways did not have at list 1 boy.
In the other  ways, there was at least one boy.
Maybe there was just 1 boy, being the first child, or the second one, or...
Maybe there were 2 boys, or 3. or...., and they were born in some order or other.
The possible ways to have one or more boys are  ,
and there is only way to not have at least 1 boy.
|
|
|
